Is it good to run in Seattle in May?

Yes, it's one of the better months to run here. The typical daytime Run Score is 91 (Great), with temperatures around 55°F (13°C) and comfortable dew points. The best window is usually 6–11 AM.

How hot is it for running in Seattle in May?

Typical temperatures average 55°F (13°C) (Ideal) with dew points near 47°F. Dew point (not the thermometer) usually decides how hard the run feels.

What is a good Run Score?

Scores run 0–100. 80–100 is Great (97+ earns a gold star for near-perfect conditions). 65–79 (Good) is solid. 55–64 (Fair) or 45–54 (Tough) means at least one factor (usually heat or dew point) is slowing you. Below 45 (Poor), expect a noticeably harder effort or hold back for safety.

Why does dew point matter more than temperature?

Your body cools by evaporating sweat. When the dew point climbs above roughly 60°F, the air is too saturated for sweat to evaporate efficiently, so heat builds up even if the thermometer looks reasonable. That's why a 70°F muggy morning can feel harder than a dry 80°F afternoon.

Running in Seattle in May

Typical May running conditions in Seattle, and a live Run Score so you can see how today compares with the norm.

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One check a day, done for you

When to go
Every hour gets a Run Score. On this Austin day the best was 7 am at 94.
Why it feels hard
Tap any hour: what's against you and how much slower the same effort runs.
On your home screen
Widgets and a morning alert, no app to open.

RunWeather Today in Austin at 7 am: Run Score 94, great day to run

7 am · score 94

Why this score: 57 out of 100, 6.8% slower for the same effort, temperature is the biggest drag

3 pm · 6.8% slower

Typical Run Score

Great

Avg temperature

55°F

Ideal

Avg dew point

47°F

Comfortable

Best window

6–11 AM

Local time

How May compares in Seattle

May ranks 2nd of 12 months for running in Seattle, with a typical daytime Run Score of 91 (Great). For reference, the best month is October (score 93) and the hardest is July (score 74). The kindest window in May is typically 6–11 AM. Precipitation falls in roughly 18% of hours this month. Use the live tool below to see how today actually compares with the May norm.

Climate data by Open-Meteo.com, from Copernicus ERA5 reanalysis, hourly 2022–2024 (CC BY 4.0). RunWeather computed the Run Scores, best windows and monthly averages from it.

By city

Best time to run, by city

What the calculator scores
Eight signals, weighted by how much each changes a run
Temperature. Performance peaks near 50–54°F. Every degree above that works your cooling system harder and slows the pace you can hold at the same effort.
Dew point. The real humidity signal. Above ~60°F dew point, sweat stops evaporating efficiently: the single biggest hidden driver of a hard summer run.
Wind. Sustained wind and gusts feed drag and thermal estimates. This public calculator uses a default route-exposure assumption because it does not know your running direction.
Heat stress. How hard heat, humidity, sun, and wind hit your body, combined into one number (wet-bulb globe temperature), the same metric race directors use to flag risk.
Solar exposure. Direct radiation on a shadeless route can feel far hotter than the air temperature. Cloud cover and sun angle are factored in.
Precipitation. Rain probability and intensity affect footing, comfort, and gear, weighted by how likely it is during your window.
Air quality. US AQI is folded in so sensitive runners get a clear signal when particulates make hard efforts a bad idea.
Pace adjustment. The output you actually use: how many seconds per mile to ease off today so your effort (not the clock) stays honest.
Enter your city. Search any city worldwide. RunWeather pulls the live local forecast: temperature, dew point, wind, sun, and air quality.
Get a 0–100 Run Score. One number that blends performance, safety, and experience (labeled Great, Good, Fair, Tough, or Poor) for the current hour.
Scrub the next 12 hours. Tap any hour to rebuild the full breakdown for that start time, or jump straight to the best window today.
Need a pace target for the heat instead? Try the heat and humidity pace calculator.
Running guides
Heat, humidity, wind, cold
Questions runners ask
4 questions
Is it good to run in Seattle in May?
Yes, it's one of the better months to run here. The typical daytime Run Score is 91 (Great), with temperatures around 55°F (13°C) and comfortable dew points. The best window is usually 6–11 AM.
How hot is it for running in Seattle in May?
Typical temperatures average 55°F (13°C) (Ideal) with dew points near 47°F. Dew point (not the thermometer) usually decides how hard the run feels.
What is a good Run Score?
Scores run 0–100. 80–100 is Great (97+ earns a gold star for near-perfect conditions). 65–79 (Good) is solid. 55–64 (Fair) or 45–54 (Tough) means at least one factor (usually heat or dew point) is slowing you. Below 45 (Poor), expect a noticeably harder effort or hold back for safety.
Why does dew point matter more than temperature?
Your body cools by evaporating sweat. When the dew point climbs above roughly 60°F, the air is too saturated for sweat to evaporate efficiently, so heat builds up even if the thermometer looks reasonable. That's why a 70°F muggy morning can feel harder than a dry 80°F afternoon.
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Running in Seattle in May

One check a day, done for you

When to go

Why it feels hard

On your home screen

How May compares in Seattle

Best time to run, by city

How the score works

What the calculator scores

Running guides

Questions runners ask

Is it good to run in Seattle in May?

How hot is it for running in Seattle in May?

What is a good Run Score?

Why does dew point matter more than temperature?

From the blog

Know your best hour before you head out.