Bothell West climate — normals and trends
Bothell West (United States) has a warm-summer mediterranean climate (Csb) under the Köppen-Geiger classification. Its mean annual temperature is 10.4 °C and it receives 1,421 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 August (17.1 °C on average) and the coldest is January (4.6 °C). Rainfall peaks in November.
Bothell West averages 14 frost days, 1 hot days (≥ 30 °C) and 165 rainy days per year.
Bothell West has warmed by +1.5 °C between 1940 and 2025, or +0.18 °C per decade. This trend is statistically significant.
The number of frost days there went from about 19 to 9 per year over the period.
The hottest day of the period reached 36.6 °C (on 29 July 2009) and the coldest -15.1 °C (on 21 December 1990).
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
Bothell WestWashington
- coords
- 47.81°, -122.24°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
10.4°C
Average daily high
13.9°C
Average daily low
7.4°C
Annual rainfall
1,421mm
Sunshine / day
8.6h
Mean relative humidity
78%
Average peak wind
15.3km/h
Seasonal range
12.5°C
Frost days (< 0 °C)
14 d/yr
Hot days (≥ 30 °C)
1 d/yr
Rainy days (≥ 1 mm)
165 d/yr
Annual snowfall
28.7 cm
Average feels-like high
12.2 °C
Average feels-like low
5.0 °C
Average peak gust
29.4 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
12.2 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.5 °C
since 1940
+0.2 °C per decade · r² = 0.43 · 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
36.6 °C
29 July 2009
Coldest day
-15.1 °C
21 December 1990
Wettest day
85 mm
23 November 1986
Windiest day
55.1 km/h
12 December 1995
Strongest gust
99.4 km/h
20 January 1993
Hottest feels-like
39.2 °C
29 July 2009
Coldest feels-like
-20.9 °C
16 December 1964
Snowiest day
18.2 cm
20 January 1943
Sunniest day
15.7 h
17 June 2025
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 | 7.1 °C | +0.3 °C | 74 mm | -113 mm |
| Feb | 7.4 °C | -1.1 °C | 139 mm | -2 mm |
| Mar | 11.2 °C | +0.8 °C | 181 mm | +44 mm |
| Apr | 14.4 °C | +1.5 °C | 89 mm | -21 mm |
| May | 16.9 °C | +0.7 °C | 79 mm | -5 mm |
| Jun | 20.0 °C | +1.4 °C | 21 mm | -49 mm |
| Jul | 23.2 °C | +1.4 °C | 10 mm | -24 mm |
| Aug | 22.9 °C | +1.0 °C | 82 mm | +40 mm |
| Sep | 20.6 °C | +1.5 °C | 31 mm | -45 mm |
| Oct | 14.2 °C | 0.0 °C | 141 mm | -6 mm |
| Nov | 11.4 °C | +1.9 °C | 224 mm | +24 mm |
| Dec | 9.3 °C | +2.4 °C | 305 mm | +110 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 Bothell West?
Bothell West has a warm-summer mediterranean climate (Köppen Csb). Over 1940-2025, the average annual temperature is 10.4 °C and it receives 1,421 mm of precipitation per year.
What is the hottest day ever recorded in Bothell West?
The hottest day measured in Bothell West between 1940 and 2025 was 29 July 2009, reaching 36.6 °C.
What is the coldest day in Bothell West?
The coldest day measured in Bothell West between 1940 and 2025 was 21 December 1990, at -15.1 °C.
Does it snow in Bothell West?
Yes. Bothell West gets on average 28.7 cm of snow per year and has around 14 frost days.
Has the climate of Bothell West warmed?
Yes: Bothell West warmed by +1.5 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Bothell West?
The wettest day measured in Bothell West between 1940 and 2025 was 23 November 1986, with 85 mm of rain in 24 hours.
What was the windiest day in Bothell West?
The windiest day measured in Bothell West between 1940 and 2025 was 12 December 1995, with winds reaching 55.1 km/h.
What is the warmest month in Bothell West?
The warmest month in Bothell West is August (17.1 °C on average); the coldest is January (4.6 °C).
How much does it rain in Bothell West?
Bothell West receives on average 1,421 mm of precipitation per year, spread over about 165 rainy days.
Is it sunny in Bothell West?
Bothell West gets on average 8.6 hours of sunshine per day, roughly 3,139 hours per year over 1940-2025.
What is the biggest single-day snowfall in Bothell West?
The heaviest 24-hour snowfall measured in Bothell West between 1940 and 2025 was 20 January 1943, with 18.2 cm.
Are there tropical nights in Bothell West?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in Bothell West.
What was the most extreme apparent temperature in Bothell West?
In Bothell West, between 1940 and 2025, the highest apparent temperature reached 39.2 °C on 29 July 2009, and the lowest was -20.9 °C on 16 December 1964.
Compare Bothell West with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Bothell West