Weather in San Diego

On this site the months that score closest to a 22°C day, lighter rain, and moderate humidity are July, August, and September. San Diego is in United States at 32.7°N. The 2001–2020 NASA POWER daily record describes a Mediterranean pattern: dry summers and wetter winters.

August is the warmest month (average 24.0°C, high 30.2°C) and December is the coolest (average 13.0°C, low 8.6°C). Rain is about 269 mm of rain spread through the year. The wettest month is February at 55 mm; the driest is August at 4 mm.

Rainfall pattern

Annual rainfall is 269 mm. February leads at 55 mm; August is lightest at 4 mm.

Humidity peaks near 68%. That usually lines up with the wetter months rather than the hottest ones.

Temperature through the year

The heat peaks in August, when the typical afternoon is 30.2°C. The opposite pole is December, when mornings average 8.6°C.

Across the year the mean afternoon high is 23.3°C. If you want the smallest day–night shock, look at months where the high and low sit close together; August nights still hold 17.7°C.

The calendar in San Diego

February is the wettest month — 55 mm and 7 rainy days, with 66% humidity. Peak heat arrives in August: 30.2°C by day, 17.7°C at night, and 57% humidity. October: 25.5°C high, 14.9°C low, 15 mm rain, 60% humidity.

In November, San Diego averages 21.5°C by day and 11.7°C at night, with 25 mm of rain. The year bottoms out in December. Plan for 8.6°C at night and 17.5°C in the afternoon.

When the score favours a visit

The three months with the highest comfort score are July, August, and September: July (23.2°C average, 4 mm, 58% humidity); August (24.0°C average, 4 mm, 57% humidity); September (23.4°C average, 6 mm, 57% humidity). They fall in calendar order. The score rewards averages near 22°C, lower rainfall, and humidity near 60%. It is a climate score, not a festival or price calendar.

If you prefer the hottest stretch, that is August. The coolest stretch is December.

San Diego and other cities in United States

Los Angeles is about 179 km away: San Diego is 0.5°C cooler than Los Angeles in its hottest month and 63 mm drier over the year than Los Angeles. Los Angeles’s wettest month is February (75 mm) versus February here.

Phoenix is about 481 km away: San Diego is 9.9°C cooler than Phoenix in its hottest month and a similar annual rainfall (256 mm in Phoenix). Phoenix’s wettest month is August (34 mm) versus February here.

San Antonio is about 1813 km away: San Diego is 6.0°C cooler than San Antonio in its hottest month and 511 mm drier over the year than San Antonio. San Antonio’s wettest month is May (100 mm) versus February here.