San Diego, CA Climate & Monthly Averages
The climate of San Diego
Located in California, United States, San Diego experiences a semi-arid climate with big day-to-night temperature swings and modest rainfall. Afternoon temperatures peak near 78°F (26°C) in August and dip to about 64°F (18°C) in January, with around 13.3 inches (337 mm) of precipitation falling across the year.
Climate quick facts
- Hottest month: August - highs near 78°F (26°C)
- Coldest month: January - highs near 64°F (18°C)
- Record high: 98°F (37°C) · Record low: 35°F (2°C) (2015–2024)
- Wettest month: January (6 rainy days) · Sunniest: July (12.4 h sun/day)
- Climate type: semi-arid - big day-to-night temperature swings and modest rainfall
Temperatures through the year
The warmest stretch of the year centers on August. Highs average 78°F (26°C) and overnight lows stay near 66°F (19°C). The coolest month is January, with typical highs of 64°F (18°C) and lows around 48°F (9°C). Based on 2015–2024 weather data, temperatures have reached as high as 98°F (37°C) and dropped as low as 35°F (2°C).
Rain, sun and snow
January is usually the wettest month. It brings about 2.9 inches (73 mm) of rain over 6 days, while June is the driest. July brings the most sunshine, averaging 12.4 hours of sun a day.
Monthly climate table
| Month | High | Low | Rain days | Precipitation | Sunshine | Humidity |
|---|---|---|---|---|---|---|
| January | 64° | 48° | 6 | 2.9 in | 8.6 h/day | 73% |
| February | 65° | 48° | 5 | 2.1 in | 9.3 h/day | 70% |
| March | 65° | 51° | 8 | 2.2 in | 10.2 h/day | 75% |
| April | 68° | 54° | 3 | 0.8 in | 10.9 h/day | 73% |
| May | 68° | 57° | 3 | 0.6 in | 11.0 h/day | 75% |
| June | 72° | 61° | 0 | 0.1 in | 11.9 h/day | 76% |
| July | 76° | 65° | 0 | 0.2 in | 12.4 h/day | 78% |
| August | 78° | 66° | 0 | 0.3 in | 11.7 h/day | 78% |
| September | 78° | 65° | 1 | 0.4 in | 10.7 h/day | 77% |
| October | 76° | 60° | 2 | 0.4 in | 9.9 h/day | 72% |
| November | 70° | 53° | 4 | 1.1 in | 9.4 h/day | 65% |
| December | 64° | 48° | 5 | 2.2 in | 8.3 h/day | 70% |
San Diego month by month
San Diego weather in January
January brings highs around 64°F (18°C), lows near 48°F (9°C), about 6 wet days - typically the coldest month and the wettest month of the year in San Diego.
San Diego weather in February
February brings highs around 65°F (18°C), lows near 48°F (9°C), about 5 wet days.
San Diego weather in March
March brings highs around 65°F (18°C), lows near 51°F (11°C), about 8 wet days.
San Diego weather in April
April brings highs around 68°F (20°C), lows near 54°F (12°C), about 3 wet days.
San Diego weather in May
May brings highs around 68°F (20°C), lows near 57°F (14°C), about 3 wet days.
San Diego weather in June
June brings highs around 72°F (22°C), lows near 61°F (16°C), about 0 wet days - typically the driest month of the year in San Diego.
San Diego weather in July
July brings highs around 76°F (24°C), lows near 65°F (18°C), about 0 wet days - typically the sunniest month of the year in San Diego.
San Diego weather in August
August brings highs around 78°F (26°C), lows near 66°F (19°C), about 0 wet days - typically the hottest month of the year in San Diego.
San Diego weather in September
September brings highs around 78°F (26°C), lows near 65°F (18°C), about 1 wet days.
San Diego weather in October
October brings highs around 76°F (24°C), lows near 60°F (16°C), about 2 wet days.
San Diego weather in November
November brings highs around 70°F (21°C), lows near 53°F (12°C), about 4 wet days.
San Diego weather in December
December brings highs around 64°F (18°C), lows near 48°F (9°C), about 5 wet days.
Seasons in San Diego
Spring (March through May)
Spring in San Diego is mild, with daytime highs averaging 67°F (19°C) and nights around 54°F (12°C); rain falls on about 14 days over the three months.
Summer (June through August)
Summer in San Diego is mild and warm, with daytime highs averaging 75°F (24°C) and nights around 64°F (18°C); precipitation is infrequent.
Fall (September through November)
Fall in San Diego is pleasantly warm, with daytime highs averaging 75°F (24°C) and nights around 59°F (15°C); precipitation is infrequent.
Winter (December through February)
Winter in San Diego is crisp but comfortable, with daytime highs averaging 64°F (18°C) and nights around 48°F (9°C); rain falls on about 16 days over the three months.
Climate questions, answered
What is the average temperature in San Diego?
Is San Diego hot in summer?
Is San Diego cold in winter?
How many rainy days does San Diego get in a year?
Best time to visit San Diego
The best time to visit San Diego is generally January to June, when temperatures are at their most comfortable before or after the peak heat. Daytime temperatures in that window typically sit near 67°F (19°C).
Pack for San Diego with light layers that can adapt to mild swings through the day. Evenings can feel noticeably cooler than afternoons - August nights average 66°F (19°C).
San Diego temperature records (2015-2024)
Derived from ERA5 reanalysis data, 2015–2024. Official station records may differ.