Seattle, WA Climate & Monthly Averages
Seattle has an oceanic climate. August is the hottest month, averaging 77° by day; December is the coldest at 45°.
How weather changes through the year in Seattle
Seattle runs on a dry-summer rhythm: the warmest months are also the driest. July averages 14 mm (0.6 in) while the wet season peaks in December at 7.4 inches (189 mm). Highs range from 45°F (7°C) to 77°F (25°C).
Seattle climate quick facts
- Hottest month: August - highs near 77°F (25°C)
- Coldest month: December - highs near 45°F (7°C)
- Decade extremes (2015-2024): 100°F (38°C) high · 14°F (-10°C) low
- Wettest month: December (19 rainy days) · Sunniest: July (12.7 h sun/day)
- Climate type: oceanic
- Annual swing: 14°C between the average warmest and coolest month · day to night: 7°C
- Snow: about 7 days a year
- Average humidity: 77%
Temperatures, rain and sunshine
Sunshine averages 8.0 hours a day over the year - duller than about 83% of the cities we track, peaking in July at 12.7 hours. December sits at the other end of the year: 45°F (7°C) by day, 37°F (3°C) at night. August is the warm end of the year, averaging 77°F (25°C) by day and 59°F (15°C) overnight.
The gridded 2015-2024 daily record for this location tops out at 100°F (38°C) and bottoms at 14°F (-10°C) - decade extremes, not all-time station records. Precipitation concentrates in December - 7.4 inches (189 mm) on 19 days - and thins out by July.
Four of the twelve months pair mild highs with fewer than twelve wet days; the longest unbroken run is June through September.
Where Seattle sits among other climates
- Seattle sits close to the middle of our dataset on most measures: 52°F (11°C) as an annual average, 47.4 inches (1203 mm) of precipitation and 8.0 hours of sun a day.
These comparisons use the same ten-year window for every city in the dataset.
Monthly climate table
| Month | High | Low | Rain days | Precipitation | Sunshine | Daylight | Wet-day chance | Humidity |
|---|---|---|---|---|---|---|---|---|
| January | 47° | 37° | 18 | 7.3 in | 4.1 h/day | 8.8 h | 59% | 84% |
| February | 47° | 36° | 15 | 4.9 in | 5.1 h/day | 10.2 h | 54% | 82% |
| March | 52° | 39° | 15 | 4.3 in | 7.5 h/day | 11.8 h | 49% | 80% |
| April | 57° | 42° | 14 | 3.3 in | 9.2 h/day | 13.6 h | 48% | 77% |
| May | 64° | 49° | 10 | 2.1 in | 10.1 h/day | 15.1 h | 32% | 74% |
| June | 70° | 54° | 8 | 2.0 in | 11.7 h/day | 16.0 h | 28% | 70% |
| July | 76° | 58° | 3 | 0.6 in | 12.7 h/day | 15.6 h | 11% | 66% |
| August | 77° | 59° | 5 | 1.1 in | 11.5 h/day | 14.3 h | 16% | 68% |
| September | 69° | 55° | 10 | 2.5 in | 9.2 h/day | 12.5 h | 35% | 76% |
| October | 59° | 48° | 14 | 5.0 in | 6.5 h/day | 10.7 h | 46% | 82% |
| November | 50° | 41° | 18 | 6.9 in | 4.7 h/day | 9.2 h | 59% | 83% |
| December | 45° | 37° | 19 | 7.4 in | 3.6 h/day | 8.4 h | 62% | 84% |
Seattle month by month
Each card shows the average high and low. The bar places that month between Seattle's coldest night and warmest afternoon.
January
- Rain
- 18 days
- Sunshine
- 4.1 h
- Daylight
- 8.8 h
- Snow
- 1 day
February
- Rain
- 15 days
- Sunshine
- 5.1 h
- Daylight
- 10.2 h
- Snow
- 2 days
March
- Rain
- 15 days
- Sunshine
- 7.5 h
- Daylight
- 11.8 h
April
- Rain
- 14 days
- Sunshine
- 9.2 h
- Daylight
- 13.6 h
May
- Rain
- 10 days
- Sunshine
- 10.1 h
- Daylight
- 15.1 h
June
- Rain
- 8 days
- Sunshine
- 11.7 h
- Daylight
- 16.0 h
July
- Rain
- 3 days
- Sunshine
- 12.7 h
- Daylight
- 15.6 h
August
- Rain
- 5 days
- Sunshine
- 11.5 h
- Daylight
- 14.3 h
September
- Rain
- 10 days
- Sunshine
- 9.2 h
- Daylight
- 12.5 h
October
- Rain
- 14 days
- Sunshine
- 6.5 h
- Daylight
- 10.7 h
November
- Rain
- 18 days
- Sunshine
- 4.7 h
- Daylight
- 9.2 h
December
- Rain
- 19 days
- Sunshine
- 3.6 h
- Daylight
- 8.4 h
- Snow
- 2 days
Looking for warmer alternatives? Browse warm places by month, or compare Seattle's coolest part of the year: December, January, February.
A season-by-season guide to Seattle
Spring (March through May)
Spring is crisp but comfortable here - highs near 58°F (14°C), nights near 43°F (6°C), and rain falls on around 39 of the 90 days.
Summer (June through August)
Summer in Seattle settles into easy warmth, with daytime highs averaging 74°F (23°C) and nights around 57°F (14°C); rain comes on about 17 days over the three months. Daylight is generous - around 12.0 hours of sun a day.
Fall (September through November)
Fall stays on the cool side of mild here - highs near 59°F (15°C), nights near 48°F (9°C), and rain falls on around 42 of the 90 days.
Winter (December through February)
Winter is brisk and cold here - highs near 46°F (8°C), nights near 37°F (3°C), and rain falls on around 53 of the 90 days, plus about 6 snowy days.
Questions people ask about Seattle's climate
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The most useful weather window for Seattle
Best time to visit Seattle
The best time to visit Seattle is generally May to September, when the dry season is running but the afternoons are still bearable. Daytime temperatures in that window sit near 71°F (22°C), with rain on about 7 days a month. For the same question asked the other way round, see where else is warm in May.
What to pack
Pack for Seattle with a warm jacket and layers for the cooler season and proper waterproofs rather than an umbrella - wet days are the norm here. Note the gap between afternoon and night: August pairs 77°F (25°C) with 59°F (15°C).
Seattle temperature extremes in the 2015–2024 dataset
Derived from ERA5 reanalysis data, 2015–2024. Official station records may differ. Need another precipitation unit? Use the rainfall converter.