Sunnyside climate — normals and trends
Sunnyside (United States) has a hot-summer mediterranean continental climate (Dsa) under the Köppen-Geiger classification. Its mean annual temperature is 11.9 °C and it receives 273 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 (25.0 °C on average) and the coldest is January (-0.3 °C). Rainfall peaks in December.
Sunnyside averages 83 frost days, 63 hot days (≥ 30 °C) and 64 rainy days per year.
Sunnyside has warmed by +2.2 °C between 1940 and 2025, or +0.26 °C per decade. This trend is statistically significant.
The number of frost days there went from about 95 to 71 per year over the period.
The hottest day of the period reached 46.7 °C (on 29 June 2021) and the coldest -30.4 °C (on 2 February 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
SunnysideWashington
- coords
- 46.32°, -120.01°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
11.9°C
Average daily high
17.7°C
Average daily low
6.3°C
Annual rainfall
273mm
Sunshine / day
10.0h
Mean relative humidity
55%
Average peak wind
14.7km/h
Seasonal range
25.3°C
Frost days (< 0 °C)
83 d/yr
Hot days (≥ 30 °C)
63 d/yr
Rainy days (≥ 1 mm)
64 d/yr
Annual snowfall
30.2 cm
Average feels-like high
14.9 °C
Average feels-like low
3.3 °C
Average peak gust
32.8 km/h
Tropical nights (≥ 20 °C)
10 d/yr
Solar radiation
16.3 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.2 °C
since 1940
+0.3 °C per decade · r² = 0.49 · 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
46.7 °C
29 June 2021
Coldest day
-30.4 °C
2 February 1950
Wettest day
40 mm
21 December 1964
Windiest day
52.4 km/h
8 January 1990
Strongest gust
109.4 km/h
24 March 1976
Hottest feels-like
46.9 °C
29 June 2021
Coldest feels-like
-35.3 °C
17 January 1950
Snowiest day
19.3 cm
19 November 1996
Sunniest day
15.6 h
13 June 1940
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 | 4.6 °C | +1.3 °C | 29 mm | -12 mm |
| Feb | 6.4 °C | -1.1 °C | 38 mm | +8 mm |
| Mar | 14.5 °C | +1.9 °C | 35 mm | +9 mm |
| Apr | 20.8 °C | +3.1 °C | 12 mm | -9 mm |
| May | 25.2 °C | +1.9 °C | 6 mm | -13 mm |
| Jun | 30.9 °C | +3.3 °C | 0 mm | -12 mm |
| Jul | 34.5 °C | +2.0 °C | 7 mm | +3 mm |
| Aug | 33.8 °C | +2.5 °C | 7 mm | +1 mm |
| Sep | 30.2 °C | +4.1 °C | 6 mm | -4 mm |
| Oct | 17.2 °C | -0.5 °C | 20 mm | -3 mm |
| Nov | 10.6 °C | +1.9 °C | 37 mm | -2 mm |
| Dec | 8.8 °C | +5.0 °C | 69 mm | +26 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 Sunnyside?
Sunnyside has a hot-summer mediterranean continental climate (Köppen Dsa). Over 1940-2025, the average annual temperature is 11.9 °C and it receives 273 mm of precipitation per year.
What is the hottest day ever recorded in Sunnyside?
The hottest day measured in Sunnyside between 1940 and 2025 was 29 June 2021, reaching 46.7 °C.
What is the coldest day in Sunnyside?
The coldest day measured in Sunnyside between 1940 and 2025 was 2 February 1950, at -30.4 °C.
Does it snow in Sunnyside?
Yes. Sunnyside gets on average 30.2 cm of snow per year and has around 83 frost days.
Has the climate of Sunnyside warmed?
Yes: Sunnyside warmed by +2.2 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Sunnyside?
The wettest day measured in Sunnyside between 1940 and 2025 was 21 December 1964, with 40 mm of rain in 24 hours.
What was the windiest day in Sunnyside?
The windiest day measured in Sunnyside between 1940 and 2025 was 8 January 1990, with winds reaching 52.4 km/h.
What is the warmest month in Sunnyside?
The warmest month in Sunnyside is July (25.0 °C on average); the coldest is January (-0.3 °C).
How much does it rain in Sunnyside?
Sunnyside receives on average 273 mm of precipitation per year, spread over about 64 rainy days.
Is it sunny in Sunnyside?
Sunnyside gets on average 10.0 hours of sunshine per day, roughly 3,650 hours per year over 1940-2025.
What is the biggest single-day snowfall in Sunnyside?
The heaviest 24-hour snowfall measured in Sunnyside between 1940 and 2025 was 19 November 1996, with 19.3 cm.
Are there tropical nights in Sunnyside?
Yes: Sunnyside has on average 10 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Sunnyside?
In Sunnyside, between 1940 and 2025, the highest apparent temperature reached 46.9 °C on 29 June 2021, and the lowest was -35.3 °C on 17 January 1950.
Compare Sunnyside with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Sunnyside