San Luis Obispo climate — normals and trends
San Luis Obispo (United States) has a warm-summer mediterranean climate (Csb) under the Köppen-Geiger classification. Its mean annual temperature is 14.5 °C and it receives 412 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 (18.1 °C on average) and the coldest is January (10.9 °C). Rainfall peaks in January.
San Luis Obispo averages 0 frost days, 2 hot days (≥ 30 °C) and 38 rainy days per year.
San Luis Obispo has warmed by +0.8 °C between 1940 and 2025, or +0.09 °C per decade. This trend is statistically significant.
The hottest day of the period reached 36.6 °C (on 13 September 1948) and the coldest -2.0 °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
San Luis ObispoCalifornia
- coords
- 35.28°, -120.66°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
14.5°C
Average daily high
18.6°C
Average daily low
11.3°C
Annual rainfall
412mm
Sunshine / day
11.2h
Mean relative humidity
74%
Average peak wind
16.6km/h
Seasonal range
7.2°C
Frost days (< 0 °C)
0 d/yr
Hot days (≥ 30 °C)
2 d/yr
Rainy days (≥ 1 mm)
38 d/yr
Annual snowfall
0.0 cm
Average feels-like high
17.8 °C
Average feels-like low
9.7 °C
Average peak gust
33.6 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
20.1 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+0.8 °C
since 1940
+0.1 °C per decade · r² = 0.19 · 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
13 September 1948
Coldest day
-2.0 °C
22 December 1990
Wettest day
116 mm
5 December 1997
Windiest day
53.6 km/h
3 February 1998
Strongest gust
124.6 km/h
3 February 1998
Hottest feels-like
36.6 °C
6 September 2020
Coldest feels-like
-7.5 °C
22 December 1990
Snowiest day
1.5 cm
22 January 1962
Sunniest day
14.0 h
18 May 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 | 16.0 °C | +1.1 °C | 10 mm | -75 mm |
| Feb | 16.3 °C | +1.0 °C | 80 mm | -5 mm |
| Mar | 15.0 °C | -0.9 °C | 73 mm | +1 mm |
| Apr | 16.1 °C | -1.0 °C | 9 mm | -19 mm |
| May | 18.6 °C | +0.3 °C | 0 mm | -7 mm |
| Jun | 18.5 °C | -1.8 °C | 0 mm | -2 mm |
| Jul | 17.7 °C | -4.2 °C | 0 mm | -0 mm |
| Aug | 21.4 °C | -1.0 °C | 0 mm | -1 mm |
| Sep | 21.4 °C | -1.1 °C | 10 mm | +6 mm |
| Oct | 20.0 °C | -1.2 °C | 27 mm | +12 mm |
| Nov | 18.0 °C | 0.0 °C | 82 mm | +40 mm |
| Dec | 17.4 °C | +2.1 °C | 106 mm | +36 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 San Luis Obispo?
San Luis Obispo has a warm-summer mediterranean climate (Köppen Csb). Over 1940-2025, the average annual temperature is 14.5 °C and it receives 412 mm of precipitation per year.
What is the hottest day ever recorded in San Luis Obispo?
The hottest day measured in San Luis Obispo between 1940 and 2025 was 13 September 1948, reaching 36.6 °C.
What is the coldest day in San Luis Obispo?
The coldest day measured in San Luis Obispo between 1940 and 2025 was 22 December 1990, at -2.0 °C.
Does it snow in San Luis Obispo?
Almost never: San Luis Obispo sees virtually no snow, with about 0 frost days per year.
Has the climate of San Luis Obispo warmed?
Yes: San Luis Obispo warmed by +0.8 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in San Luis Obispo?
The wettest day measured in San Luis Obispo between 1940 and 2025 was 5 December 1997, with 116 mm of rain in 24 hours.
What was the windiest day in San Luis Obispo?
The windiest day measured in San Luis Obispo between 1940 and 2025 was 3 February 1998, with winds reaching 53.6 km/h.
What is the warmest month in San Luis Obispo?
The warmest month in San Luis Obispo is August (18.1 °C on average); the coldest is January (10.9 °C).
How much does it rain in San Luis Obispo?
San Luis Obispo receives on average 412 mm of precipitation per year, spread over about 38 rainy days.
Is it sunny in San Luis Obispo?
San Luis Obispo 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 San Luis Obispo?
The heaviest 24-hour snowfall measured in San Luis Obispo between 1940 and 2025 was 22 January 1962, with 1.5 cm.
Are there tropical nights in San Luis Obispo?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in San Luis Obispo.
What was the most extreme apparent temperature in San Luis Obispo?
In San Luis Obispo, between 1940 and 2025, the highest apparent temperature reached 36.6 °C on 6 September 2020, and the lowest was -7.5 °C on 22 December 1990.
Compare San Luis Obispo with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around San Luis Obispo