San Diego, California weather in September

Averages from 2021–2025 (150 days of record).

Average high: 77°F
Average low: 65°F
Rainy days: ~2 per month
Total precipitation: 0.9 in
Warmest recorded: 96°F
Coldest recorded: 57°F

Expect September days in San Diego, California to top out around 77°F and cool to about 65°F overnight, with roughly 2 days of measurable rain across the month. In recent years September has ranged from 57°F to 96°F.

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Current San Diego, California forecast → · Historical data by Open-Meteo (ERA5).