How Dog Weather works

When is a good time to walk your golden today? Dog Weather reads the forecast for Washington, DC and answers that: how it feels in the sun and in the shade, the best walk times today and tomorrow, plus heat, thunderstorms, air quality, sunny pavement and winter salt. Every line names what it rests on, and where the evidence is thin, it says so.

Dog Weather turns the forecast for Washington, DC into walk advice for a golden. This page is every rule behind it: the number that sets off each line, whose number it is, how much weight its source can bear, and what we left out on purpose. The short version: there is no heat index or pavement temperature for dogs with evidence behind it, and the one air quality scale for pets is the EPA's, adapted. Where a scale exists for people, we use it and say so. Where a line is our own choice, we mark it Ours.

This is guidance, not veterinary advice. Every golden is different, and the thresholds behind these are thinner than you would hope: there is no published heat index for dogs, and nobody has measured what temperature burns a paw. When in doubt, ask your vet, and watch your dog rather than the number.

The signals

Each signal shows only when its line is crossed. The level is always said in words: Warning, Take care, or Good to know. Like the walk times, every signal reads every hour, day and night, so a freezing 3am or a hot 11pm gets its card; sunny pavement needs daylight by its own line.

Heat

We compute the heat index from the air temperature and humidity, the way the National Weather Service does, and take the day's highest. It is a scale for people, in shade; no veterinary body publishes one for dogs. The dog evidence comes after it: goldens have 2.67 times the odds of heatstroke that Labradors do, and most dog heatstroke follows exercise, usually an ordinary walk.

Line	Where it falls	Whose
Shows as Take care	heat index 80°F or more	ours, at the NWS Caution line
Becomes a Warning	heat index 95°F or more	ours, at DC's Heat Alert line
Names the Extreme Heat Alert level	heat index 105°F or more	DC Heat Plan
The NWS bands we name	Caution 80°F, Extreme Caution 90°F, Danger 103°F, Extreme Danger 125°F	National Weather Service

NWS heat index equationStrong
NWS heat index bandsStrong
NWS on sun and the heat indexStrong
DC Heat Plan 2026Strong
Beard et al. 2024 (RVC)Strong
Hall et al. 2020, Scientific ReportsStrong
Hall et al. 2020, AnimalsStrong
RVC VetCompass 2021Strong

Sunny pavement

Marks the daylight hours when pavement is likely sitting in hot sun, so grass and shade are the cooler way through. It never prints a pavement temperature, because nobody has measured what temperature burns a paw.

Line	Where it falls	Whose
Flags an hour	daylight, UV index 3 or more, and air 80°F or warmer	Ours

Chestovich et al. 2022Strong
Washington State UniversityFolklore
American Kennel ClubFolklore
Dogs TrustFolklore

Thunderstorms

Notice, not danger. Almost a third of dogs are sensitive to noise, and the things that help (a quiet spot, an earlier walk, a plan from your vet) all need warning. The storm line comes from the National Weather Service's own forecast for your area, not the forecast model behind the rest of Dog Weather, which files DC's storm days under heavy showers. We use the Weather Service's words: possible when it gives a chance of thunderstorms (30 to 50%), likely when it says likely (60% or more). It shows as Good to know, and the homepage mentions storms only when they're likely. If the Weather Service's forecast doesn't load, or the latest we have is more than 12 hours old, the page says so instead of showing no storm line.

Line	Where it falls	Whose
Shows	a chance of thunderstorms or more in the National Weather Service forecast (30% and up)	National Weather Service
Says likely	when the Weather Service says thunderstorms are likely (60% and up)	National Weather Service
How far ahead we look	the next 48 hours	Ours
For a walk	take care when storms are possible, skip when they're likely	Ours

National Weather Service forecastStrong
NWS forecast wordingStrong
Salonen et al. 2020Strong

Air quality

The EPA's air quality index, labelled as the scale for people it is. At Good and Moderate we show the reading and nothing more. From Unhealthy for Sensitive Groups up, we add Colorado State University's advice for pets, paraphrased and credited, and we keep their word: adapted.

Line	Where it falls	Whose
The bands	Good 0, Moderate 51, Unhealthy for Sensitive Groups 101, Unhealthy 151, Very Unhealthy 201, Hazardous 301	EPA
Advice for dogs at each band	from 101	Colorado State University (adapted)
Take care, then Warning	from 101, then from 151	ours, at the EPA's lines

EPA AirNowStrong
Colorado State University 2026Moderate

Winter salt

A condition, not a temperature: salt goes down ahead of forecast snow and ice and stays down after, whatever the thermometer says. When there has been or will be snow or ice, we say salt is probably down and suggest wiping or rinsing paws after the walk, before your golden licks them.

Line	Where it falls	Whose
Shows	snow, snow showers, snow grains, freezing drizzle or freezing rain in the forecast (weather codes 56, 57, 66, 67, 71, 73, 75, 77, 85, 86), or any snowfall	the forecast itself
The window	the last 48 hours or the next 24	Ours

Merck Veterinary ManualStrong
ASPCA Animal Poison ControlStrong

Below freezing

DC law, not a vet chart. Below 32°F is "extreme weather", when a dog can't be left outside for more than 15 minutes without a person or proper shelter unless its age, condition and type let it handle the cold. That rule is about dogs left out, not walks. On a walk, salt and ice are the usual winter hazards, and puppies, seniors and sick dogs keep warm less well. When some of its hours reach DC's Extreme Cold Alert level, a line made for people, the card says they are too cold for Goldens, as the walk times do.

Line	Where it falls	Whose
Shows	air temperature below 32°F	D.C. Code § 8-1801(13)
Hours it reads	every hour, day and night, as the walk times do	Ours
Says too cold for Goldens	when any of those hours reaches DC's Extreme Cold Alert level (a forecast wind chill of 15°F, or 20°F with at least a 50% chance of rain or snow)	DC's Winter Plan

D.C. Code § 8-1801Strong
D.C. Code § 8-1808Strong
Purdue VA-16-WStrong
DC Winter Plan FY26Strong

Best walk times

Every hour, day and night, is sorted into good, take care, or skip by the weather alone; the clock plays no part. The best windows are the longest stretches of the best hours left in the day, and a day with nothing flagged says so, rather than inventing a best time. The chart's strip names each hour by what makes it so, from Good for a walk to Too hot or Too cold for Goldens.

Line	Where it falls	Whose
Hours it rates	every hour, day and night: the weather decides, not the clock	Ours
Skip	thunderstorms likely, heat index 95°F or more, a forecast wind chill at DC's Extreme Cold Alert level (15°F, or 20°F with at least a 50% chance of rain or snow), or AQI 151 or more	ours, at the lines above and DC's Winter Plan
Take care	thunderstorms possible, heat index 80°F or more, sunny pavement, AQI 101 to 150, rain 50% likely or more, or below 32°F	ours, at the lines above
Rain	50% chance or more	Ours
Named on the chart	good is Good for a walk; take care is Getting warm, be cautious (heat or sunny pavement), Getting cold, be cautious (below freezing), or Rain, storms or poor air, be cautious; skip is Too hot for Goldens, Too cold for Goldens, or Storms or unhealthy air, keep it short	Ours

Sun and shade

In the sun and In the shade are our own estimate

The two lines on the chart, and the two cards with it, show how warm it is likely to feel to a person standing in full sun, and to the same person in shade. Between the hours the chart draws each line as a smooth curve that never rises above or dips below the hours on either side, so it shows no high or low the forecast doesn't have. They are our own estimate, not a published formula. Bryan, who runs DC Goldens, built it for Vibe Temp, his weather app, and set its numbers by hand until they matched how DC actually feels outside. The walk hours never read them. The sun line picks two times and nothing else: the paw-to-grass time for a golden, only among hours the walk rules already call good, and the touch-grass time for people.

In the shade starts with the air temperature, adds 1°F for every 15 points of humidity above 40% (and takes 1°F off for every 15 points below it), and takes 0.7°F off for every mile an hour of wind. In the sun adds up to 8°F on top of that, depending on how much sun gets through, plus 1.2°F for heat bouncing back off the sidewalk whenever any does. How much sun gets through comes from the forecast: the UV index against what it would be under a clear sky, dimmed by how much of the sky counts as cloud. After sunset, and under a sky that lets no sun through, the two lines are the same.

In the shade = T + (RH - 40) / 15 - 0.7 × W
In the sun   = In the shade + 8 × S + 1.2, when S is above 0
S = (UV / clear-sky UV) × (1 - C^0.7), kept between 0 and 1, and 0 at night
C = 1 - (direct sunlight / all sunlight) / 0.85, kept between 0 and 1

T is the air temperature in °F, RH the relative humidity in %, W the wind speed in mph, and C the share of the sky that counts as cloud. Without a clear-sky UV reading, S uses the UV index over 10.

One change from Vibe Temp's version: it reads how much of the sunlight arrives as a direct beam, rather than the forecast's cloud percentage. So thin high cloud with the sun plainly out still counts as sun, and the low sun just after sunrise and before sunset counts for less. On a clear midday that moves the sun line by under a degree on average, and on a grey day hardly at all. A daylight hour that reads no sunlight at all counts as full cloud, so the two lines meet. Only when the forecast has no sunlight reading does it go back to the cloud percentage, as Vibe Temp does. The 0.85 is a first guess from DC's clear middays, and we may tune it.

It describes a person, not a dog: nobody has measured how a golden's coat changes what the sun feels like, so we don't turn it into a dog's number. The paw-to-grass time, below, applies a range we chose for a golden to the sun line, and it says so. It is not a pavement temperature, and it is not the wind chill. And it does not decide the walk hours: good, take care and skip still come from the National Weather Service's heat index, DC's Heat Alert level, the air quality, storms, rain, sunny pavement, DC's legal cold line and its Extreme Cold Alert level, as described above. On a hot, humid afternoon the heat index can read higher than even the sun line; they are different scales, and the heat index is the one DC's heat alerts use. The National Weather Service says full sun can add up to 15°F to the heat index; our sun line sits at most 9.2°F above the shade line.

Line	Where it falls	Whose
Humidity	+1°F for every 15 points above 40% (and 1°F off for every 15 below)	Ours
Wind	0.7°F off for every mile an hour	Ours
Full sun	up to +8°F, by how much sun gets through	Ours
Off the sidewalk	+1.2°F whenever any sun gets through (4 × 0.3, Vibe Temp's concrete setting)	Ours
A clear sky's direct beam	85% of all sunlight	ours, a first guess
Sun above shade, at most	9.2°F	Ours
The walk hours	never use these two numbers	the heat index, the AQI, storms, rain, sunny pavement, the air temperature and DC's Extreme Cold Alert level decide them
The paw-to-grass time	reads the sun line, only among hours the walk rules already call good	Ours
The touch-grass time	reads the sun line by Vibe Temp's rule for people	Vibe Temp's

Vibe Temp (ours)Ours
NWS on sun and the heat indexStrong

Two best times

The chart marks two times to get out on the grass, because the best time is different for a person and for a golden: a leaf for people, and a paw for Goldens.

The touch-grass time is Vibe Temp's rule for people

The leaf marks the best time for a person to get outside, by the rule Bryan wrote for Vibe Temp, his weather app, brought over as closely as this site allows. Vibe Temp reads its In the sun line every 15 minutes, on a straight line between the hourly values, rounded to a tenth of a degree, and looks only at daylight times from 65 to 75°F (18 to 24°C). Each scores 100, less 10 for every degree it sits from 70°F, and a time from 10am to 5pm scores 20 more. The best score on each day wins, and a tie keeps the earlier time. The 24-hour view shows the best in the next 24 hours, and the 7-day view one on each day. No walk rule applies to it: it is for people, and Vibe Temp has none.

Where ours differs from Vibe Temp's, each because this site's chart differs: the sun line it reads is ours, with the direct-beam change described under Sun and shade. Daylight runs from each day's sunrise to its sunset, to the minute, where Vibe Temp goes by the hour. It scores in degrees Fahrenheit even when the page shows Celsius, where Vibe Temp switches to 18 to 24°C. It only looks ahead from now, where Vibe Temp marks today's best even after it has passed. The 24-hour view shows one best in the next 24 hours, where Vibe Temp marks each calendar day's. Vibe Temp draws its sun line onto the shade line wherever the two are within 5% of each other, and its rule reads that drawn line; ours reads the sun line as it is. And the leaf sits on the smooth line the chart draws, which curves between the hours where the rule reads a straight one, so the leaf can sit a little off the reading it names: on DC's days in 2025, under half a degree nine times in ten, and never more than a degree and a half.

Line	Where it falls	Whose
Where it can sit	a point every 15 minutes (:00, :15, :30, :45), from now on, in daylight from sunrise to sunset	Vibe Temp's points; daylight to the minute and from now on are ours
The line it reads	In the sun, straight between the hourly values and rounded to a tenth of a degree; in degrees Fahrenheit, whichever units the page shows	Vibe Temp's rule, on our sun line; °F in either unit is ours
The range	65°F (18°C) to 75°F (24°C), both included	Vibe Temp's
The score	100, less 10 for every degree from 70°F (21°C), plus 20 from 10am to 5pm	Vibe Temp's
How many	the best score in the next 24 hours; in the next 7 days, each day's best; a tie keeps the earlier time; or none, and the page says why	Vibe Temp's each-day best and tie rule; the single 24-hour pick and the reasons are ours
The walk rules	play no part: it is for people	Vibe Temp's

Vibe Temp (ours)Ours

The paw-to-grass time is our own pick

The paw marks one time: the best time for a golden to get out on the grass. It sits on the chart's In the sun line, at the minute the line comes closest to 57°F (14°C), in daylight (from sunrise to sunset) and where our walk rules call the hours on either side of it good. The forecast gives one reading an hour, so a minute between two of them is read off the smooth line the chart draws through them: an estimate from the curve, no more exact than the two hours it joins. Anything from 45 to 64°F (7 to 18°C) can hold it, judged in whole degrees Fahrenheit whichever units the page shows, and a tie goes to the earlier minute. The 7-day view puts a paw on each day's own best time and names the week's best. When nothing in the next 24 hours (or the next 7 days, on the week view) fits, there is no paw, and we say why.

The range is our choice. No study sets one, and the researchers closest to the question say advice on safe temperatures for exercising dogs is missing. What the evidence does say points cooler than a person. A resting dog holds its temperature without effort from about 68 to 86°F (20 to 30°C), and a walk adds heat it mostly has to pant away. At UK canicross races where the air averaged 48°F (9°C), at least one running dog per race finished with an ear temperature above 105°F (40.6°C). And goldens had 2.67 times the odds of heat-related illness of Labradors. So we aimed 13°F below the 70°F that Vibe Temp aims for a person, stopped the range at 64°F, and let it reach further on the cool side than the warm side, because the evidence of harm for goldens is on the warm side.

We score the In the sun line, the warmer of our two, because a golden on open grass is usually in the sun. The UK study of dogs seen for heat-related illness read each day's weather at shaded weather stations, which its authors say likely understate what a dog meets; the canicross temperature above was measured on the course, out of the shade. Both lines estimate how it feels to a person; nobody has measured how a golden's coat takes the sun. The paw is a pleasant time for a walk, not a safe temperature and not a veterinary threshold: dogs in these studies overheated on mild days too.

Line	Where it falls	Whose
Where it can sit	any minute from now on in daylight, sunrise to sunset, between hours the walk rules call good	Ours
The line it reads	In the sun, to the minute, as the chart draws it between the hourly forecasts; in whole degrees Fahrenheit, whichever units the page shows	Ours
The range	45°F (7°C) to 64°F (18°C)	Ours
The aim	57°F (14°C); a tie goes to the earlier minute	Ours
How many	one in the next 24 hours; in the next 7 days, one on each day that has a time that fits; or none, and the page says why	Ours

Vibe Temp (ours)Ours
Hall 2024 (thesis)Strong
Purdue VA-16-WStrong
Carter and Hall 2018Strong
Hall et al. 2020, Scientific ReportsStrong
Hall et al. 2022, Veterinary SciencesStrong

Our own lines

Where no source sets a number, we had to pick one. These are those picks, said plainly.

The sunny-pavement hours are our line

We flag an hour as sunny pavement when it is daytime, the UV index is 3 or more and the air is 80°F or warmer. No study sets that line. It marks the hours when the combination researchers measured, direct sun on a hot day, is plausible, and it never produces a pavement temperature.

Chestovich et al. 2022Strong

Walk windows are our own combination

Every hour is rated by the weather alone, day and night; the clock plays no part. An hour is one to skip when the National Weather Service says thunderstorms are likely, when the heat index reaches DC's Heat Alert level (95°F), when a forecast wind chill reaches DC's Extreme Cold Alert level (15°F, or 20°F with at least a 50% chance of rain or snow), or when the AQI is 151 or more. It is one to take care in when thunderstorms are possible, the heat index is 80°F or more, the pavement is in sun, the AQI is 101 to 150, rain is 50% likely or more, or it is below freezing. The chart names each hour by its cause: Good for a walk; Getting warm, Getting cold, or Rain, storms or poor air, each with be cautious; and Too hot for Goldens, Too cold for Goldens, or Storms or unhealthy air, keep it short. The best windows are the longest stretches of the best hours left in the day. The 50% rain line is ours, and so is borrowing DC's heat and cold alert levels, which are set for people, for a golden; the others borrow the sources below.

DC Heat Plan 2026Strong
DC Winter Plan FY26Strong
NWS heat index bandsStrong
EPA AirNowStrong
Chestovich et al. 2022Strong
D.C. Code § 8-1801Strong
NWS forecast wordingStrong

The homepage weather note is our shortlist

The homepage mentions the weather only when, between now and the end of tomorrow, it reaches something serious for people: a heat index at DC's Heat Alert level (95°F) or Extreme Heat Alert level (105°F), a forecast wind chill at DC's Extreme Cold Alert level (15°F, or 20°F with at least a 50% chance of rain or snow), freezing rain or drizzle, heavy snow, thunderstorms the National Weather Service calls likely, or an AQI of 151 or more. It reads DC's forecast from ZIP 20009 for everyone, and on an ordinary day it shows nothing at all. Which items make the list is our choice; each number on it is DC's or the EPA's, ice and heavy snow are the forecast's own weather codes, and storms are the National Weather Service's own word.

DC Heat Plan 2026Strong
DC Winter Plan FY26Strong
NWS wind chill chartStrong
EPA AirNowStrong
NWS forecast wordingStrong

How far ahead, and how fresh

We show 7 days ahead at most. Past about a week, the forecast's rain chance and its weather code come from different models and start to disagree, so a meetup further out gets its panel as the day comes into range. A meetup's panel reads the meetup's own hours when its time is written as clock times, and the whole day when it isn't; we never guess an hour. The panel on a spot or neighborhood page reads the same 24 hours as its chart, so its cards run past midnight and never rate the heat or the air above what the chart shows. A stretch still going at the chart's edge is followed to when it ends, as far as the last day we show; one still going then reads "through at least" that day. The forecast is refreshed every 3 hours, and if refreshing keeps failing, we stop showing one more than 12 hours old rather than pass off an old forecast as today's. The National Weather Service's storm forecast is refreshed every hour, and one it last updated more than 12 hours ago is not shown; the page says the storm forecast didn't load instead.

What we left out, and why

Each of these is easy to find elsewhere. None of them holds up for dogs.

Why there is no pavement temperature

The pavement tables that circulate trace back to a 1970 report on three people burned on Phoenix asphalt: a study of people, not paws. Nobody has measured what surface temperature burns a dog's paw, so we show where the sun is instead of a number. The back-of-hand test is a fine habit; the published advice says 5, 7 or 10 seconds, and none of those counts was tested.

Berens 1970Strong
Chestovich et al. 2022Strong
Washington State UniversityFolklore
American Kennel ClubFolklore
Dogs TrustFolklore

Why there is no wind chill

The wind chill index models wind at the height of an adult's face and is built on a human face. A golden's double coat is exactly what it leaves out, so we show air temperature and DC's legal line instead. We work it out in one place only: to tell when the forecast reaches DC's Extreme Cold Alert level, which the District writes in wind chill for people. The homepage note and the walk times' Too cold for Goldens both read that level, and we never print it. Borrowing a line set for people for a golden is our choice, as it is for heat. Wind does take some warmth off our In the shade estimate for a person, which is our own line, not the wind chill.

NWS wind chill chartStrong
D.C. Code § 8-1801Strong
DC Winter Plan FY26Strong

Why there is no pollen count

Our weather source only has pollen for Europe, and the one study built to test pollen counts against itching in allergic dogs found no link. A golden walks with its nose in the grass; the count comes from a trap on a roof.

Open-Meteo air quality docsStrong
Widorn et al. 2024Strong

Why there is no “too hot to walk” temperature

A chart saying to take care above about 20°C and not to walk a dog above 25°C is shared widely. We could not trace it to any study. Most dog heatstroke follows exercise, usually an ordinary walk, so what a golden is doing matters alongside the thermometer, and one number can't carry that. We show the heat index, name it as a scale for people, and put the dog evidence beside it.

Hall et al. 2020, AnimalsStrong

Why there is no ground temperature

Our weather source offers a ground-surface temperature. It is a model of a whole patch of the city, grass and trees and roofs as well as roads, not a reading of the asphalt your golden walks on, and no one has set a line for it. A bare number would invite a question nobody can answer, so we leave it out.

Credits and data

The forecast is Open-Meteo's, fetched by our server, never by your browser, so no weather service ever sees who is looking. Places in the same patch of about 11 km share one forecast, which usually moves the temperature by less than a degree. Air quality comes from the Copernicus Atmosphere Monitoring Service through the same service. Thunderstorms come from the National Weather Service's own forecast for your area, which our server fetches the same way; the Weather Service's data is public domain.

A place is Washington, DC or a neighborhood you pick from the list, in DC or the nearby Maryland and Virginia suburbs, or something the page already knows: a Dog Guide spot's own map point, or a meetup's spot. We read a neighborhood's forecast at its central ZIP, and the city's at 20009, as we do for a DC meetup without a spot. The last group in the list, Getaways, is for places more than 50 miles out that the pack visits (Dewey Beach, DE), each read at the town itself. Getaways use the same levels as everywhere else here, which are DC's. We never ask your device where it is.

Every forecast on the site carries one small link, to Open-Meteo, beside the numbers. The rest of the credits are here.

The forecast
Weather data by Open-Meteo.com, licensed CC BY 4.0 (Open-Meteo's licence page). We changed it: we convert the units, work out our own In the sun and In the shade estimate from it, and apply our own rules for the walk hours, the signals and the two best times. The dog guidance on these pages is DC Goldens' own reading of Open-Meteo's forecast, not Open-Meteo's.
Air quality
Contains modified Copernicus Atmosphere Monitoring Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains. It reaches us through Open-Meteo, which turns it into the US AQI, and we sort that into the EPA's categories and the walk flags. Used under the Licence to Use Copernicus Products.
Thunderstorms
Thunderstorm forecast by the National Weather Service, from the gridded forecast kept by its office for each place, Baltimore/Washington's for DC. Its data is public domain, so nothing requires this credit; we give it anyway.
The air quality scale and the advice for pets
The categories are the EPA's AirNow AQI Basics, a scale made for people. The advice for dogs from Unhealthy for Sensitive Groups up is Colorado State University's 2026 adapted index, paraphrased; their chart is theirs.
ZIP code locations
US Census Bureau ZIP Code Tabulation Areas, 2020, public domain, kept as a table in our own code, so a ZIP never leaves our server to be looked up.
In the sun and In the shade
Our own model, from Vibe Temp, the weather app Bryan, who runs DC Goldens, built; its code is public. How it works is under Sun and shade, above.

Why storms come from the National Weather Service

The forecast model behind the rest of Dog Weather files DC's storm days under heavy showers: from January 2024 to September 2026 it never forecast an hour of thunder here, while Reagan National Airport recorded thunder on 119 days. So the storm line reads the National Weather Service's own forecast instead. Over May to September of 2025 and 2026, its Baltimore/Washington office gave at least a chance of thunderstorms a day ahead on 63 of the 69 days thunder was heard at the airport. It also gave a chance on about 40 days that stayed quiet there, which is what a 30 to 50% chance looks like, so we say possible, not coming. The comparison is ours, and small: one airport, two summers and nothing from the colder months, scored against the Weather Service's archived forecasts for that airport rather than the feed the site reads today.

Iowa Environmental MesonetStrong
Open-Meteo forecast docsStrong
NWS forecast wordingStrong

Sources

Every source a line on Dog Weather rests on, with how much we think it can bear. Strong: measured data or black-letter law; Moderate: a single site, a news write-up of work not yet peer reviewed, or an extrapolation; Folklore: advice that circulates with no study behind it; Ours: DC Goldens' own work, tuned by hand and not peer reviewed. The grading is ours.

Strong2022
The Heat Index Equation
NOAA Weather Prediction Center
The formula we compute the heat index with, from air temperature and humidity. It is a scale for people, in shade.
Strong2026
Heat Index
National Weather Service, Amarillo
The Caution, Extreme Caution, Danger and Extreme Danger bands for people. An older NWS brochure starts Danger at 105°F instead of 103°F.
Strong2026
What is the heat index?
National Weather Service
The heat index assumes shade and light wind; full sun can add up to 15°F.
Strong2026
2026 District of Columbia Heat Plan
DC Department of Human Services, HSEMA and the Interagency Council on Homelessness
DC's Heat Alert starts at a forecast heat index of 95°F and its Extreme Heat Alert at 105°F. We say when a forecast reaches that level; only DC can issue an alert.
Strong2024
Epidemiology of heat-related illness in dogs under UK emergency veterinary care in 2022
Beard, Hall, Bradbury, Carter, Gilbert and O'Neill, Veterinary Record (RVC VetCompass)
Five times as many dog heatstroke cases a day during the UK's human heat-health alerts. Measured against UK alerts, not DC's.
Strong2020
Incidence and risk factors for heat-related illness (heatstroke) in UK dogs under primary veterinary care in 2016
Hall, Carter and O'Neill, Scientific Reports
Golden retrievers had 2.67 times the odds of heat-related illness of Labradors (905,543 dogs); the authors suggest the thicker coat may be the tipping factor.
Strong2020
Dogs Don't Die Just in Hot Cars: Exertional Heat-Related Illness (Heatstroke) Is a Greater Threat to UK Dogs
Hall, Carter and O'Neill, Animals
Exercise was the most common trigger of heat-related illness in UK dogs (74.2% of events), and 67.5% of exercise cases with a known activity followed a walk. Goldens were not a significant breed in its models, so we cite it for walks, not for goldens.
Strong2021
Recognising early signs of heatstroke in dogs can save lives
Royal Veterinary College VetCompass, reporting Hall et al., Scientific Reports
The early signs are breathing changes and lethargy, such as not wanting to exercise; 98% of dogs seen at that stage survived.
Strong2022
Temperature Profiles of Sunlight-Exposed Surfaces in a Desert Climate: Determining the Risk for Pavement Burns
Chestovich, Saroukhanoff, Moujaes, Flores, Carroll and Saquib, Journal of Burn Care & Research
Sunlit surfaces ran 36 to 56°F hotter than the same material in shade, measured at the same moment on a 120°F day, and sun plus heat, not air temperature alone, is what makes a surface dangerous. Measured in Las Vegas; the absolute numbers do not transfer to DC.
Folklore2017
Protect your pet's feet from heat, burns
Washington State University College of Veterinary Medicine
The back-of-hand test at seven seconds. No study behind the count.
Folklore2021
How to Protect Dog Paws From Hot Pavement
American Kennel Club
The same test at ten seconds. No study behind the count.
Folklore2026
Caring for your dog during hot weather
Dogs Trust
The same test at five seconds. No study behind the count.
Strong1970
Thermal contact burns from streets and highways
Berens, JAMA
Where the popular pavement tables trace back to: a report on three people burned on Phoenix asphalt, about people rather than paws. Abstract and metadata verified; the full text is paywalled, so we do not claim what its inner pages hold.
Strong2022
Risk Factors for Severe and Fatal Heat-Related Illness in UK Dogs: A VetCompass Study
Hall, Carter, Chico, Bradbury, Gentle, Barfield and O'Neill, Veterinary Sciences
On the days UK dogs were seen for heat-related illness, the day's highest wet bulb globe temperature ranged from 3.3 to 23.1°C, a median of 16.9°C: dogs overheat on mild days. That is a heat-stress index read at shaded weather stations, which the authors say likely understate what a dog meets, not an air temperature. Read 2026-09-24.
Strong2018
Investigating factors affecting the body temperature of dogs competing in cross country (canicross) races in the UK
Carter and Hall, Journal of Thermal Biology
108 dogs over 10 winter race days: at every race at least one dog finished with an ear temperature above 40.6°C (105°F). Hard running in harness, not a walk. Read 2026-09-24.
Strong2024
Hot Dogs: Advancing the Epidemiology and Clinical Definition of Heat-Related Illness in UK Dogs
Emily J. Hall, PhD thesis, Nottingham Trent University
Says advice on safe temperatures for exercising with dogs is lacking (p. 100), and puts the air at those canicross races at 8.8°C (48°F) on average. Coat colour and length made no significant difference once each dog was counted once. Read 2026-09-24.
Strong2020
Prevalence, comorbidity, and breed differences in canine anxiety in 13,700 Finnish pet dogs
Salonen et al., Scientific Reports
Noise sensitivity affects 32% of dogs and grows with age, fear of thunder especially.
Strong2026
API Web Service
National Weather Service
Where the thunderstorm forecast comes from: the gridded forecast each Weather Service office keeps for its area, Baltimore/Washington for DC. Free and public domain. Read 2026-09-24.
Strong2020
Point Forecast Matrices Product Specifications
National Weather Service
What the Weather Service's forecast words mean: slight chance 20% or less, chance 30 to 50%, likely 60 to 70%, and 80 to 100% with no qualifier (Table 4). Read 2026-09-24.
Strong2026
Iowa Environmental Mesonet
Iowa State University, Department of Agronomy
Keeps the history our storm comparison used: the Weather Service's archived point forecasts for Reagan National, from its Baltimore/Washington office, and the airport's hourly reports of thunder. The archive is theirs; the comparison is ours. Read 2026-09-24.
Strong2026
Weather Forecast API documentation
Open-Meteo
The forecast's weather codes: 95 and 97 are thunderstorms, and 96 and 99 (with hail) come only from models with a hail forecast, such as DWD ICON or UKMO. Read 2026-09-24.
Strong2026
AQI Basics
US EPA AirNow
The six AQI categories, from Good to Hazardous. A scale for people.
Moderate2026
Do you know how poor air quality affects pets? Learn through this adapted index
Colorado State University College of Veterinary Medicine and Biomedical Sciences
Dr. Colleen Duncan and colleagues adapted the EPA scale for pets, with advice for each band. A news story, not a peer-reviewed paper; paraphrased here, and their chart is theirs.
Strong2022
Salt Toxicosis in Animals
Merck Veterinary Manual
In dogs the lethal dose of salt is about 4 g/kg, and signs can appear after 2 to 3 g/kg.
Strong2000
Ice melts are health hazards (Toxicology Brief)
Hautekeete, ASPCA Animal Poison Control Center, in Veterinary Medicine
A dog that walked through ice melt should be bathed and watched for skin irritation; 4 g/kg of sodium chloride can be lethal.
Strong2026
D.C. Code § 8-1801, Definitions
Council of the District of Columbia
Section (13): extreme weather means below 32°F or above 90°F. Air temperature; no wind chill.
Strong2026
D.C. Code § 8-1808, Prohibited conduct
Council of the District of Columbia
Section (c)(1): no leaving an animal outdoors without a person or adequate shelter for more than 15 minutes in extreme weather, unless its age, condition and type let it withstand it. It does not limit walks.
Strong2016
Temperature Requirements for Dogs (VA-16-W)
Jordan, Bauer, Stella and Croney, Purdue University Center for Animal Welfare Science
Cold tolerance varies widely by coat: the lower critical temperature is below 0°C (32°F) for a husky and 15°C (59°F) for some short-haired dogs. It also gives, from the National Research Council, the range where a dog keeps its temperature without spending effort on it: 20 to 30°C (68 to 86°F). Housing numbers for dogs at rest, not on a walk.
Strong2026
Wind Chill Chart
National Weather Service
The wind chill index works at the height of an adult's face and is based on a human face model.
Strong2025
District of Columbia Winter Plan, FY26
DC Interagency Council on Homelessness, with HSEMA
DC's Extreme Cold Alert (once the Cold Weather Emergency) is called when the NWS forecasts a wind chill of 15°F or below, or 16 to 20°F with at least a 50% chance of rain, snow, freezing rain or sleet (§2.2). Its Cold Alert starts at a wind chill of 32°F, or 40°F with at least a 50% chance of precipitation (§2.1). Alerts for people; only DC can call one. Read 2026-09-24.
Ours2025
Vibe Temp
Bryan Casler, who runs DC Goldens
Our own sun and shade model for a person, tuned by hand against how DC feels, with public code, and the touch-grass rule that picks the best time for a person to be outside. Not a published formula and not peer reviewed. We changed how it reads cloud; the Sun and shade section says how. Read 2026-09-24; its touch-grass rule read 2026-09-25.
Strong2024
A prospective study evaluating the correlation between local weather conditions, pollen counts and pruritus of dogs with atopic dermatitis
Widorn, Zabolotski and Mueller, Veterinary Dermatology
Found no correlation between pollen counts and itch in allergic dogs, and questions whether rooftop pollen traps reflect a dog's exposure at ground level.
Strong2026
Air Quality API documentation
Open-Meteo
Pollen is only available for Europe; for DC every pollen value comes back empty (checked live).

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