Seattle climate — normals and trends
Seattle (United States) has a warm-summer mediterranean climate (Csb) under the Köppen-Geiger classification. Its mean annual temperature is 10.9 °C and it receives 1,376 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is July (18.4 °C on average) and the coldest is January (4.5 °C). Rainfall peaks in November.
Seattle averages 18 frost days, 4 hot days (≥ 30 °C) and 161 rainy days per year.
Seattle has warmed by +1.4 °C between 1940 and 2025, or +0.17 °C per decade. This trend is statistically significant.
The number of frost days there went from about 24 to 12 per year over the period.
The hottest day of the period reached 38.3 °C (on 28 June 2021) and the coldest -15.9 °C (on 25 January 1950).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
SeattleWashington
- coords
- 47.61°, -122.33°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
10.9°C
Average daily high
14.7°C
Average daily low
7.7°C
Annual rainfall
1,376mm
Sunshine / day
8.5h
Mean relative humidity
78%
Average peak wind
13.8km/h
Seasonal range
13.9°C
Frost days (< 0 °C)
18 d/yr
Hot days (≥ 30 °C)
4 d/yr
Rainy days (≥ 1 mm)
161 d/yr
Annual snowfall
28.3 cm
Average feels-like high
13.2 °C
Average feels-like low
5.5 °C
Average peak gust
31.5 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
12.4 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.4 °C
since 1940
+0.2 °C per decade · r² = 0.37 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
38.3 °C
28 June 2021
Coldest day
-15.9 °C
25 January 1950
Wettest day
85 mm
25 November 1998
Windiest day
49.7 km/h
12 December 1995
Strongest gust
110.9 km/h
20 January 1993
Hottest feels-like
42.1 °C
28 June 2021
Coldest feels-like
-20.7 °C
25 January 1950
Snowiest day
22.4 cm
18 November 1946
Sunniest day
15.7 h
20 June 2024
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | 7.4 °C | +0.6 °C | 70 mm | -115 mm |
| Feb | 7.6 °C | -1.1 °C | 136 mm | -5 mm |
| Mar | 11.5 °C | +0.7 °C | 194 mm | +55 mm |
| Apr | 15.0 °C | +1.4 °C | 87 mm | -21 mm |
| May | 17.6 °C | +0.4 °C | 63 mm | -16 mm |
| Jun | 21.1 °C | +1.1 °C | 18 mm | -44 mm |
| Jul | 24.4 °C | +1.0 °C | 5 mm | -22 mm |
| Aug | 24.1 °C | +0.6 °C | 60 mm | +24 mm |
| Sep | 21.4 °C | +1.0 °C | 29 mm | -42 mm |
| Oct | 14.7 °C | -0.3 °C | 152 mm | +14 mm |
| Nov | 11.6 °C | +1.8 °C | 190 mm | -8 mm |
| Dec | 9.5 °C | +2.4 °C | 300 mm | +108 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Seattle?
Seattle has a warm-summer mediterranean climate (Köppen Csb). Over 1940-2025, the average annual temperature is 10.9 °C and it receives 1,376 mm of precipitation per year.
What is the hottest day ever recorded in Seattle?
The hottest day measured in Seattle between 1940 and 2025 was 28 June 2021, reaching 38.3 °C.
What is the coldest day in Seattle?
The coldest day measured in Seattle between 1940 and 2025 was 25 January 1950, at -15.9 °C.
Does it snow in Seattle?
Yes. Seattle gets on average 28.3 cm of snow per year and has around 18 frost days.
Has the climate of Seattle warmed?
Yes: Seattle warmed by +1.4 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Seattle?
The wettest day measured in Seattle between 1940 and 2025 was 25 November 1998, with 85 mm of rain in 24 hours.
What was the windiest day in Seattle?
The windiest day measured in Seattle between 1940 and 2025 was 12 December 1995, with winds reaching 49.7 km/h.
What is the warmest month in Seattle?
The warmest month in Seattle is July (18.4 °C on average); the coldest is January (4.5 °C).
How much does it rain in Seattle?
Seattle receives on average 1,376 mm of precipitation per year, spread over about 161 rainy days.
Is it sunny in Seattle?
Seattle gets on average 8.5 hours of sunshine per day, roughly 3,103 hours per year over 1940-2025.
What is the biggest single-day snowfall in Seattle?
The heaviest 24-hour snowfall measured in Seattle between 1940 and 2025 was 18 November 1946, with 22.4 cm.
Are there tropical nights in Seattle?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in Seattle.
What was the most extreme apparent temperature in Seattle?
In Seattle, between 1940 and 2025, the highest apparent temperature reached 42.1 °C on 28 June 2021, and the lowest was -20.7 °C on 25 January 1950.
Compare Seattle with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Seattle