East Palo Alto climate — normals and trends
East Palo Alto (United States) has a warm-summer mediterranean climate (Csb) under the Köppen-Geiger classification. Its mean annual temperature is 13.9 °C and it receives 504 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 (17.7 °C on average) and the coldest is January (9.5 °C). Rainfall peaks in January.
East Palo Alto averages 0 frost days, 8 hot days (≥ 30 °C) and 56 rainy days per year.
East Palo Alto has warmed by +1.0 °C between 1940 and 2025, or +0.12 °C per decade. This trend is statistically significant.
The hottest day of the period reached 40.6 °C (on 3 September 1950) and the coldest -3.6 °C (on 22 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
East Palo AltoCalifornia
- coords
- 37.47°, -122.14°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
13.9°C
Average daily high
18.6°C
Average daily low
10.3°C
Annual rainfall
504mm
Sunshine / day
10.7h
Mean relative humidity
77%
Average peak wind
13.7km/h
Seasonal range
8.2°C
Frost days (< 0 °C)
0 d/yr
Hot days (≥ 30 °C)
8 d/yr
Rainy days (≥ 1 mm)
56 d/yr
Annual snowfall
0.1 cm
Average feels-like high
18.0 °C
Average feels-like low
9.0 °C
Average peak gust
34.1 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
18.4 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.0 °C
since 1940
+0.1 °C per decade · r² = 0.27 · 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
40.6 °C
3 September 1950
Coldest day
-3.6 °C
22 December 1990
Wettest day
82 mm
13 October 2009
Windiest day
44.0 km/h
3 December 1983
Strongest gust
115.6 km/h
12 December 1995
Hottest feels-like
40.5 °C
14 June 2000
Coldest feels-like
-8.1 °C
9 December 1972
Snowiest day
1.4 cm
13 March 1975
Sunniest day
14.2 h
30 June 2010
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 | 15.2 °C | +1.9 °C | 12 mm | -80 mm |
| Feb | 15.5 °C | +0.8 °C | 108 mm | +17 mm |
| Mar | 15.7 °C | -0.1 °C | 90 mm | +8 mm |
| Apr | 17.0 °C | -0.3 °C | 16 mm | -28 mm |
| May | 19.3 °C | +0.2 °C | 4 mm | -13 mm |
| Jun | 19.6 °C | -1.9 °C | 0 mm | -4 mm |
| Jul | 20.4 °C | -2.8 °C | 0 mm | -1 mm |
| Aug | 22.7 °C | -0.6 °C | 2 mm | 0 mm |
| Sep | 23.3 °C | -0.4 °C | 3 mm | -1 mm |
| Oct | 20.6 °C | -0.7 °C | 36 mm | +12 mm |
| Nov | 17.1 °C | +0.3 °C | 81 mm | +22 mm |
| Dec | 13.7 °C | +0.1 °C | 55 mm | -30 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 East Palo Alto?
East Palo Alto has a warm-summer mediterranean climate (Köppen Csb). Over 1940-2025, the average annual temperature is 13.9 °C and it receives 504 mm of precipitation per year.
What is the hottest day ever recorded in East Palo Alto?
The hottest day measured in East Palo Alto between 1940 and 2025 was 3 September 1950, reaching 40.6 °C.
What is the coldest day in East Palo Alto?
The coldest day measured in East Palo Alto between 1940 and 2025 was 22 December 1990, at -3.6 °C.
Does it snow in East Palo Alto?
Almost never: East Palo Alto sees virtually no snow, with about 0 frost days per year.
Has the climate of East Palo Alto warmed?
Yes: East Palo Alto warmed by +1.0 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in East Palo Alto?
The wettest day measured in East Palo Alto between 1940 and 2025 was 13 October 2009, with 82 mm of rain in 24 hours.
What was the windiest day in East Palo Alto?
The windiest day measured in East Palo Alto between 1940 and 2025 was 3 December 1983, with winds reaching 44.0 km/h.
What is the warmest month in East Palo Alto?
The warmest month in East Palo Alto is September (17.7 °C on average); the coldest is January (9.5 °C).
How much does it rain in East Palo Alto?
East Palo Alto receives on average 504 mm of precipitation per year, spread over about 56 rainy days.
Is it sunny in East Palo Alto?
East Palo Alto gets on average 10.7 hours of sunshine per day, roughly 3,905 hours per year over 1940-2025.
What is the biggest single-day snowfall in East Palo Alto?
The heaviest 24-hour snowfall measured in East Palo Alto between 1940 and 2025 was 13 March 1975, with 1.4 cm.
Are there tropical nights in East Palo Alto?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in East Palo Alto.
What was the most extreme apparent temperature in East Palo Alto?
In East Palo Alto, between 1940 and 2025, the highest apparent temperature reached 40.5 °C on 14 June 2000, and the lowest was -8.1 °C on 9 December 1972.
Compare East Palo Alto with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around East Palo Alto