San Diego is warmest in August, averaging 31° by day and 18° at night. The wettest month is March with 78 mm, and the year brings about 324 mm in total.
Month by month
| Month | High | Low | Rain | Sea | Daylight | Good for |
|---|---|---|---|---|---|---|
| January | 18° | 9° | 56 mm | 15° | 10.1 h | Sightseeing |
| February | 18° | 9° | 39 mm | 15° | 10.8 h | Sightseeing |
| March | 18° | 10° | 78 mm | 15° | 11.8 h | Sightseeing |
| April | 21° | 11° | 18 mm | 16° | 12.8 h | Sightseeing |
| May | 22° | 12° | 3 mm | 18° | 13.7 h | Sightseeing |
| June | 26° | 14° | 54 mm | 20° | 14.1 h | Beach weather |
| July | 30° | 17° | 3 mm | 22° | 14.0 h | Beach weather |
| August | 31° | 18° | 12 mm | 22° | 13.2 h | Beach weather |
| September | 29° | 18° | 6 mm | 22° | 12.2 h | Beach weather |
| October | 26° | 16° | 6 mm | 20° | 11.2 h | Beach weather |
| November | 22° | 12° | 15 mm | 18° | 10.3 h | Sightseeing |
| December | 19° | 9° | 34 mm | 16° | 9.9 h | Sightseeing |
High and low are average daily maximum and minimum, rain is typical monthly total, sea is the average surface temperature, daylight is the hours between sunrise and sunset mid-month. Climate normals from NASA POWER and NOAA MUR — averages, not promises.
When to go
Beach weather: June, July, August, September and October — highs around 29°, nights no colder than 14°, and at most 54 mm of rain in a month. The sea sits at 20–22° then.
Walking the city: January, February, March, April, May, November and December — highs of 18–22° and no more than 78 mm of rain a month.