La Mesa climate — normals and trends
La Mesa (United States) has a cold semi-arid climate (BSk) under the Köppen-Geiger classification. Its mean annual temperature is 16.6 °C and it receives 311 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 (21.9 °C on average) and the coldest is January (12.2 °C). Rainfall peaks in February.
La Mesa averages 0 frost days, 16 hot days (≥ 30 °C) and 40 rainy days per year.
La Mesa has warmed by +1.5 °C between 1940 and 2025, or +0.17 °C per decade. This trend is statistically significant.
The hottest day of the period reached 40.4 °C (on 26 September 1963) and the coldest -0.8 °C (on 4 January 1949).
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
La MesaCalifornia
- coords
- 32.77°, -117.02°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
16.6°C
Average daily high
21.6°C
Average daily low
12.8°C
Annual rainfall
311mm
Sunshine / day
11.2h
Mean relative humidity
68%
Average peak wind
15.1km/h
Seasonal range
9.7°C
Frost days (< 0 °C)
0 d/yr
Hot days (≥ 30 °C)
16 d/yr
Rainy days (≥ 1 mm)
40 d/yr
Annual snowfall
0.1 cm
Average feels-like high
21.2 °C
Average feels-like low
11.8 °C
Average peak gust
32.8 km/h
Tropical nights (≥ 20 °C)
14 d/yr
Solar radiation
20.5 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.5 °C
since 1940
+0.2 °C per decade · r² = 0.38 · 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
40.4 °C
26 September 1963
Coldest day
-0.8 °C
4 January 1949
Wettest day
72 mm
10 September 1976
Windiest day
53.3 km/h
20 December 1977
Strongest gust
99.4 km/h
20 December 1977
Hottest feels-like
40.9 °C
5 September 1984
Coldest feels-like
-5.4 °C
4 January 1949
Snowiest day
2.5 cm
25 January 1949
Sunniest day
13.9 h
10 July 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 | 18.2 °C | +0.8 °C | 15 mm | -42 mm |
| Feb | 19.3 °C | +1.8 °C | 32 mm | -29 mm |
| Mar | 16.8 °C | -1.1 °C | 98 mm | +42 mm |
| Apr | 18.9 °C | -0.6 °C | 19 mm | -7 mm |
| May | 21.5 °C | +0.6 °C | 9 mm | -0 mm |
| Jun | 23.8 °C | +0.4 °C | 2 mm | +0 mm |
| Jul | 24.7 °C | -1.6 °C | 2 mm | -0 mm |
| Aug | 27.0 °C | 0.0 °C | 16 mm | +13 mm |
| Sep | 25.9 °C | -0.5 °C | 15 mm | +9 mm |
| Oct | 23.8 °C | 0.0 °C | 11 mm | -3 mm |
| Nov | 21.3 °C | +0.6 °C | 84 mm | +54 mm |
| Dec | 20.7 °C | +2.8 °C | 29 mm | -17 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 La Mesa?
La Mesa has a cold semi-arid climate (Köppen BSk). Over 1940-2025, the average annual temperature is 16.6 °C and it receives 311 mm of precipitation per year.
What is the hottest day ever recorded in La Mesa?
The hottest day measured in La Mesa between 1940 and 2025 was 26 September 1963, reaching 40.4 °C.
What is the coldest day in La Mesa?
The coldest day measured in La Mesa between 1940 and 2025 was 4 January 1949, at -0.8 °C.
Does it snow in La Mesa?
Almost never: La Mesa sees virtually no snow, with about 0 frost days per year.
Has the climate of La Mesa warmed?
Yes: La Mesa warmed by +1.5 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in La Mesa?
The wettest day measured in La Mesa between 1940 and 2025 was 10 September 1976, with 72 mm of rain in 24 hours.
What was the windiest day in La Mesa?
The windiest day measured in La Mesa between 1940 and 2025 was 20 December 1977, with winds reaching 53.3 km/h.
What is the warmest month in La Mesa?
The warmest month in La Mesa is August (21.9 °C on average); the coldest is January (12.2 °C).
How much does it rain in La Mesa?
La Mesa receives on average 311 mm of precipitation per year, spread over about 40 rainy days.
Is it sunny in La Mesa?
La Mesa gets on average 11.2 hours of sunshine per day, roughly 4,088 hours per year over 1940-2025.
What is the biggest single-day snowfall in La Mesa?
The heaviest 24-hour snowfall measured in La Mesa between 1940 and 2025 was 25 January 1949, with 2.5 cm.
Are there tropical nights in La Mesa?
Yes: La Mesa has on average 14 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in La Mesa?
In La Mesa, between 1940 and 2025, the highest apparent temperature reached 40.9 °C on 5 September 1984, and the lowest was -5.4 °C on 4 January 1949.
Compare La Mesa with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around La Mesa