Eureka climate — normals and trends
Eureka (United States) has a warm-summer mediterranean climate (Csb) under the Köppen-Geiger classification. Its mean annual temperature is 11.4 °C and it receives 1,274 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 September (14.0 °C on average) and the coldest is January (9.3 °C). Rainfall peaks in December.
Eureka averages 0 frost days, 0 hot days (≥ 30 °C) and 106 rainy days per year.
No statistically significant temperature trend emerges for Eureka between 1940 and 2025: over this span, year-to-year swings outweigh the climate signal.
The hottest day of the period reached 28.9 °C (on 28 September 2020) and the coldest -3.1 °C (on 5 February 1989).
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
EurekaCalifornia
- coords
- 40.80°, -124.16°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
11.4°C
Average daily high
13.3°C
Average daily low
9.8°C
Annual rainfall
1,274mm
Sunshine / day
9.9h
Mean relative humidity
84%
Average peak wind
21.3km/h
Seasonal range
4.7°C
Frost days (< 0 °C)
0 d/yr
Hot days (≥ 30 °C)
0 d/yr
Rainy days (≥ 1 mm)
106 d/yr
Annual snowfall
1.8 cm
Average feels-like high
11.6 °C
Average feels-like low
7.2 °C
Average peak gust
35.5 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
16.7 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
No clear trend over this period
Over a short window, year-to-year swings outweigh the climate signal. Try 86 years.
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
28.9 °C
28 September 2020
Coldest day
-3.1 °C
5 February 1989
Wettest day
128 mm
30 December 1954
Windiest day
60.8 km/h
12 October 1962
Strongest gust
120.6 km/h
10 November 1983
Hottest feels-like
29.9 °C
28 September 2020
Coldest feels-like
-8.3 °C
21 December 1990
Snowiest day
6.7 cm
17 January 1955
Sunniest day
14.8 h
16 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 | 12.1 °C | +0.9 °C | 124 mm | -94 mm |
| Feb | 10.5 °C | -0.9 °C | 214 mm | +38 mm |
| Mar | 11.2 °C | -0.1 °C | 294 mm | +113 mm |
| Apr | 12.0 °C | +0.3 °C | 79 mm | -17 mm |
| May | 12.3 °C | -0.6 °C | 23 mm | -31 mm |
| Jun | 13.3 °C | -1.0 °C | 4 mm | -15 mm |
| Jul | 14.8 °C | -0.6 °C | 3 mm | -2 mm |
| Aug | 16.4 °C | +0.5 °C | 4 mm | -5 mm |
| Sep | 16.9 °C | +0.7 °C | 43 mm | +22 mm |
| Oct | 15.1 °C | +0.2 °C | 80 mm | -7 mm |
| Nov | 14.1 °C | +1.2 °C | 173 mm | -5 mm |
| Dec | 12.7 °C | +1.2 °C | 270 mm | +41 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 Eureka?
Eureka has a warm-summer mediterranean climate (Köppen Csb). Over 1940-2025, the average annual temperature is 11.4 °C and it receives 1,274 mm of precipitation per year.
What is the hottest day ever recorded in Eureka?
The hottest day measured in Eureka between 1940 and 2025 was 28 September 2020, reaching 28.9 °C.
What is the coldest day in Eureka?
The coldest day measured in Eureka between 1940 and 2025 was 5 February 1989, at -3.1 °C.
Does it snow in Eureka?
Yes. Eureka gets on average 1.8 cm of snow per year and has around 0 frost days.
Has the climate of Eureka warmed?
Between 1940 and 2025, no statistically significant temperature trend emerges in Eureka.
What is the wettest day in Eureka?
The wettest day measured in Eureka between 1940 and 2025 was 30 December 1954, with 128 mm of rain in 24 hours.
What was the windiest day in Eureka?
The windiest day measured in Eureka between 1940 and 2025 was 12 October 1962, with winds reaching 60.8 km/h.
What is the warmest month in Eureka?
The warmest month in Eureka is September (14.0 °C on average); the coldest is January (9.3 °C).
How much does it rain in Eureka?
Eureka receives on average 1,274 mm of precipitation per year, spread over about 106 rainy days.
Is it sunny in Eureka?
Eureka gets on average 9.9 hours of sunshine per day, roughly 3,614 hours per year over 1940-2025.
What is the biggest single-day snowfall in Eureka?
The heaviest 24-hour snowfall measured in Eureka between 1940 and 2025 was 17 January 1955, with 6.7 cm.
Are there tropical nights in Eureka?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in Eureka.
What was the most extreme apparent temperature in Eureka?
In Eureka, between 1940 and 2025, the highest apparent temperature reached 29.9 °C on 28 September 2020, and the lowest was -8.3 °C on 21 December 1990.
Compare Eureka with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Eureka