San Diego climate

Name: San Diego
Address: US

San Diego is warmest in August, with average highs of 25 °C, and coldest in January, when nights average 8.8 °C. February is the wettest month (72 mm) and June the driest (2.0 mm). Figures are 1991–2020 climate normals.

Across a full year San Diego averages 311 mm of rain and 63 days above 25 °C.

United States · 20 m elevation · population 1,404,452 · 1991–2020 normals

Temperature below 0 °C to above 30 °C Rain band height is that month’s share of the wettest month

Warmest month August 25 °C
Coldest month January 8.8 °C
Driest month June 2 mm
Wettest month February 72 mm
Least cloud August 28 % cloud
Hottest on record September 37 °C
Coldest on record January 1.9 °C
Warmest sea August 21 °C

What to expectSan Diego through the year

San Diego has a clear annual cycle: average daily highs run from 18 °C in January to 25 °C in August, a swing of 8.6 °C in mean temperature across the year.

Counted across a normal year, 63 days a year reach 25 °C, 6 of them reach 30 °C. The warmest reading in the 1991–2020 record is 37 °C, in September.

Rain is strongly seasonal. February averages 72 mm against 2 mm in June — 37 times as much. Planning around the dry months matters more here than planning around temperature.

The sea off San Diego is warmest in August at 21 °C and coldest in February at 15 °C. Sea temperature lags the air by a month or two, which is why late summer swims warmer than early summer at the same air temperature.

Month by month

Month	Avg high	Rainfall	Cloud
January	17.7 °C	58 mm	45 %
February	17.6 °C	72 mm	49 %
March	18.1 °C	49 mm	49 %
April	19.5 °C	24 mm	44 %
May	20.4 °C	10 mm	47 %
June	22.1 °C	2 mm	36 %
July	24.4 °C	2 mm	33 %
August	25.5 °C	2 mm	28 %
September	25.2 °C	4 mm	29 %
October	23.2 °C	15 mm	35 %
November	20.5 °C	22 mm	37 %
December	17.5 °C	49 mm	42 %

Temperature month by month

Month	Avg high	Avg low	Mean	Record high	Record low	Days above 25 °C	Days above 30 °C
January	17.7 °C	8.8 °C	12.8 °C	27.7 °C	1.9 °C	1	0
February	17.6 °C	9.4 °C	13.2 °C	29.8 °C	1.9 °C	1	0
March	18.1 °C	10.6 °C	14.1 °C	31.8 °C	4.9 °C	1	0
April	19.5 °C	12.0 °C	15.4 °C	33.7 °C	4.9 °C	2	0
May	20.4 °C	13.7 °C	16.7 °C	35.0 °C	8.4 °C	2	0
June	22.1 °C	15.1 °C	18.3 °C	33.3 °C	11.3 °C	3	0
July	24.4 °C	17.3 °C	20.4 °C	35.8 °C	13.3 °C	11	0
August	25.5 °C	18.1 °C	21.4 °C	32.9 °C	13.2 °C	17	1
September	25.2 °C	17.6 °C	20.9 °C	36.6 °C	12.3 °C	14	2
October	23.2 °C	15.3 °C	18.9 °C	34.6 °C	8.5 °C	8	1
November	20.5 °C	11.9 °C	15.8 °C	32.6 °C	4.3 °C	3	0
December	17.5 °C	8.9 °C	12.9 °C	26.9 °C	2.2 °C	0	0

Rain, sun and wind month by month

Month	Rainfall	Wet days	Daylight	Cloud cover	Humidity	Wind	Sea temp
January	58 mm	6	10 h/day	45 %	75 %	15 km/h	15.3 °C
February	72 mm	6	11 h/day	49 %	76 %	17 km/h	15.1 °C
March	49 mm	6	12 h/day	49 %	78 %	17 km/h	15.5 °C
April	24 mm	4	13 h/day	44 %	74 %	17 km/h	16.1 °C
May	10 mm	2	14 h/day	47 %	75 %	16 km/h	17.3 °C
June	2 mm	0	14 h/day	36 %	77 %	15 km/h	18.6 °C
July	2 mm	1	14 h/day	33 %	78 %	15 km/h	20.2 °C
August	2 mm	1	13 h/day	28 %	78 %	15 km/h	21.0 °C
September	4 mm	1	12 h/day	29 %	78 %	15 km/h	20.5 °C
October	15 mm	2	11 h/day	35 %	75 %	15 km/h	19.3 °C
November	22 mm	3	10 h/day	37 %	72 %	15 km/h	17.5 °C
December	49 mm	6	10 h/day	42 %	74 %	14 km/h	16.0 °C

How San Diego compares

The same four figures for nearby destinations, so the numbers above have something to be read against. Summer high is the warmest month's average high; winter low is the coldest month's average low.

Destination	Summer high	Winter low	Rain per year	Days above 25 °C
San Diego	25 °C	8.8 °C	311 mm	63
Tijuana · Mexico	25 °C	9.1 °C	330 mm	46
Escondido · United States	29 °C	5.9 °C	412 mm	134
Oceanside · United States	26 °C	8.6 °C	372 mm	62
Ensenada · Mexico	28 °C	9.2 °C	296 mm	111

Where San Diego ranks

Ranking	Position	Value
Places with the best weather in North America in June	4thof 50	95/100
Places with the best weather in North America year-round	4thof 50	89/100
Places with the best weather in North America in October	10thof 50	95/100
Places with the best weather in North America in July	12thof 50	92/100
The driest places in North America in October	12thof 50	15 mm
Places with the best weather in North America in August	14thof 50	89/100

Planning a trip? See the best time to visit San Diego.

QuestionsCommon questions about San Diego’s climate

When is the best time to visit San Diego?

That depends on what you want, so the honest answer is a comparison rather than a single month. July, September, October sit closest to 20 °C on average, August is the warmest month and June the driest. The month-by-month table above has the full picture.

How hot does San Diego get?

In August, the warmest month, daily highs average 25 °C. About 6 days a year pass 30 °C. The highest value in the 1991–2020 record is 37 °C.

How cold does it get in winter?

Nights average 8.8 °C in January, the coldest month. Freezing nights are not part of a normal year here.

Which month is wettest in San Diego?

February, averaging 72 mm over 6 days with rain. The driest month is June with 2 mm. The year as a whole averages 311 mm.

Are these figures a forecast?

No. They are 1991–2020 climate normals: the average of thirty years, which describes what a month is usually like in San Diego rather than what any particular week will bring. Individual years can differ substantially from the normal.

Data sources and method

ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
Open-Meteo — Open-Meteo.com. CC BY 4.0
NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
GeoNames — GeoNames.org. CC BY 4.0

Normal period: 1991–2020
Dataset version: era5-1991-2020-scores1.1
Last processed: 1 August 2026

Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: monthly rankings, daylight hours, beach and comfort scores. Full formulas are on the methodology page.

Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.