San Diego weather in September
September is one of the best months to visit San Diego: highs of 28°C (83°F) and about 6 mm (0.2 in) of rain on average. Nights average 17°C (62°F) and cloud cover 59% (NASA POWER, 2001–2025 averages). The sea averages 21°C (70°F). It is the 3rd driest month of the year and the 3rd warmest. Compared with August, it is cooler and wetter; October brings highs of 25°C (76°F) and 15 mm (0.6 in) of rain.
Is September a good time to visit San Diego?
best month Weather score 87/100.
Yes. September is one of the best months for weather in San Diego.
Does it rain a lot in San Diego in September?
No, it is usually dry: about 6 mm (0.2 in) falls in an average September. It is the 3rd driest month of the year.
How warm is San Diego in September?
Days average 28°C (83°F) and nights 17°C (62°F).
San Diego weather by month
| Month | High | Low | Rain | Cloud | Sea | Weather |
|---|---|---|---|---|---|---|
| January | 17°C (63°F) | 8°C (46°F) | 41 mm | 50% | 15°C (58°F) | least pleasant |
| February | 17°C (63°F) | 8°C (46°F) | 55 mm | 56% | 15°C (60°F) | least pleasant |
| March | 19°C (66°F) | 9°C (48°F) | 29 mm | 60% | 16°C (61°F) | fair |
| April | 20°C (68°F) | 10°C (49°F) | 17 mm | 60% | 17°C (62°F) | best |
| May | 22°C (72°F) | 11°C (52°F) | 7 mm | 72% | 18°C (65°F) | best |
| June | 25°C (78°F) | 13°C (55°F) | 14 mm | 81% | 20°C (68°F) | fair |
| July | 29°C (84°F) | 16°C (61°F) | 4 mm | 75% | 21°C (71°F) | best |
| August | 29°C (85°F) | 17°C (62°F) | 4 mm | 69% | 22°C (71°F) | best |
| September | 28°C (83°F) | 17°C (62°F) | 6 mm | 59% | 21°C (70°F) | best |
| October | 25°C (76°F) | 14°C (57°F) | 15 mm | 54% | 19°C (65°F) | best |
| November | 21°C (69°F) | 11°C (51°F) | 25 mm | 50% | 17°C (63°F) | best |
| December | 17°C (62°F) | 8°C (46°F) | 51 mm | 51% | 16°C (61°F) | least pleasant |
Sources: 2001–2025 monthly averages from NASA POWER (MERRA-2 reanalysis), sea temperature from Open-Meteo Marine. Page updated . How we rate months