Seattle weather in May

May in Seattle: nice, a little rain, with clean air — an excellent time to visit.

Updated September 2026 · climate normals from ERA5 reanalysis

Seattle🇺🇸 United States · Pacific Northwest · City85
  1. 52Jan
  2. 58Feb
  3. 67Mar
  4. 77Apr
  5. 85May
  6. 92Jun
  7. 97Jul
  8. 95Aug
  9. 89Sep
  10. 72Oct
  11. 57Nov
  12. 49Dec

#5 of 12 months in Seattle · #477 of 1413 destinations to visit in May · comfort 85/100 (tier A)

Days
19°C
Nights
10°C
Wet days
5
Sun
10.8 h
Humidity
74%
Daylight
15 h
Seattle, United States
Photo: Stephen Leonardi · Pexels

Traveller notes on Seattle in May

Regulars describe this as the most variable month of the year here, unlike the more settled fall and winter, with two genuinely distinct outcomes possible on any given day - sunny and into the low 70s Fahrenheit, or overcast with highs stuck in the upper 50s to low 60s. Our row backs the mild, changeable average across that range, 19.1C over 9.5C nights, with 34mm of rain across 5.3 days. Regulars are consistent this is still a genuinely good time to visit, flowers in full bloom and springlike energy throughout the city, with layering the standard advice given how unpredictable a specific day can turn out. The record: humidity 74 percent, 10.8 hours of sun, a 12.6 kph wind and AQI 44.
SeventiesAndSunnyOrSixtiesAndOvercast · May · 1 month ago · Read more on Tripadvisor ↗

Other months in Seattle

Regulars call this one of the city's best-looking months on paper, and are specific about why: the rains that define this region typically hold off until mid-October, and the first week of the month is often the driest and warmest stretch, with the back half cooling off a little as it goes. Our row backs the shift, 21.4C over 12.3C nights, with 35.5mm of rain across 5.6 days - a real total, but light next to what regulars describe arriving a month later. Evenings call for a light jacket or sweatshirt once the sun goes down. The one caveat some years bring is wildfire smoke drifting in from regional fires, not present every September but enough that regulars mention checking air quality before a trip built around outdoor views. The record: 9.5 hours of sun, a 12.3 kph wind and AQI 40.
FirstWeekDriestSecondHalfCooler · September · 1 month ago · Read more on Tripadvisor ↗
Juneuary is the local word for the version of this month that feels like January, and the local claim is that summer does not start until the 5th of July - the same joke the Portland board tells, two hundred kilometres south. The instruction that follows is precise: the 30th of June is a different month from the 1st, so come at the end. Our row is kinder than the nickname. Rain is 29.5mm across 5.1 days, and there are 11.6 hours of sun inside 15.9 of daylight, so the grey is brief showers between sun breaks rather than a ceiling. What June lacks is warmth - 21.6C by day, 12C at night. The record: humidity 71 percent, a 12.5 kph wind and AQI 39.
JuneuaryOrNot · June · 1 month ago · Read more on Tripadvisor ↗
Seattle-forum threads on August are almost giddy about the weather - this and the two months around it are the reliably dry, sunny stretch of the year, with posters calling a soggy day genuinely rare and temperatures running warm without the humidity that makes other cities miserable in summer. The one recurring caveat has nothing to do with rainfall: more than one thread flags wildfire smoke as the real risk, a haze that can roll in and ruin an otherwise perfect week with no warning. Cruise-ship crowds pack Pike Place Market and the Space Needle on port days. The record backs the dry read completely: 25.2C days, 14.7C nights, just 12mm total across 1.6 days, 11.4 hours of sun and an AQI of 44 - though that AQI can spike hard on a bad smoke day, which the average doesn't show.
PikePlaceAugustRegular · August · 1 month ago · Read more on Tripadvisor ↗
Seattle forum threads describe February as genuinely mixed - some stretches bring drizzly, overcast, grey days typical of the region's wet season (which runs roughly mid-October through April), while other years bring a welcome week or so of milder, lighter-sun weather that winter-weary locals specifically look forward to. Snow chances were described as relatively low by this point in winter, with January and early February the more likely window for any accumulation. One consistent tip from posters familiar with the wider region: the northern Olympic Peninsula tends to run drier and sunnier than Seattle proper in February, a worthwhile alternative for anyone chasing better odds of sun.
PugetSoundRegular · February · 1 month ago · Read more on Tripadvisor ↗

Year-round notes are on Seattle's overview. Add your own note from Seattle's card on the map.

Seattle climate normals — May

Daytime high19°C / 66°F😎 nice
Nighttime low10°C / 49°F
Feels like (high)18°C / 64°F
Rainfall34 mm / 1.3 in🌦 some rain
Rainy days5 days
Humidity74%💧 humid
Dew point7°C / 45°F
Sunshine10.8 h/day
Daylight15.2 h
Wind13 km/h / 8 mph
Air quality (US AQI)44🍃 good

Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.

Crowds in Seattle in May

How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.

BusySeattle International Film Festival(estimated)

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Peak crowdsBusyShoulder seasonQuiet

Best months for Seattle's weather

Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).

Fair weatherSeattle's weather peaks June–August, best around July.

JFMAMJJASOND

Best weatherFair weatherToughest weather

What's on in Seattle in May

Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.

  • Festival

    Seattle International Film Festival

    8–26 May · usuallyCrowdedBook early

    Eleven days of screenings across a dozen city venues in the middle of May, and the one stretch of the year Seattle's cinemas queue down the block. Weekend tickets for the bigger titles go before the festival opens. Source ↗

  • Festival

    Northwest Folklife

    22–31 May · usuallyMusic festival

    Four free days at Seattle Center over Memorial Day weekend, several hundred acts and no headliners. It is the unofficial start of the dry half of the year. Source ↗

  • Season

    Junuary

    25 May – 4 Jul · usuallyFog seasonRisk

    The local name for the grey, cool weeks that sit on the city between late May and the Fourth of July, when the marine layer refuses to lift and everyone insists summer starts later here.

What's on around the world in May →

Nearby, and something's on

Within 300 km of Seattle — a day trip or a short hop — with something on this month. Never part of the comfort score.

Where is Seattle?

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Seattle in May — FAQ

Is May a good time to visit Seattle?
May in Seattle: nice, a little rain, with clean air — an excellent time to visit. It ranks #5 of 12 months for Seattle on SeasonMap's comfort score (85/100).
What is the weather like in Seattle in May?
In May, Seattle averages a daily high of 19.1°C and a low of 9.5°C, with about 34 mm of rain over roughly 5.3 rainy days.
What is the air quality in Seattle in May?
Seattle has a mean US Air Quality Index of about 44 in May.

Within 300 km: Victoria, BC's Whale watching season around 1 May – 15 Oct, and Portland's Portland Rose Festival around 22 May – 14 Jun.