San Jose, California weather in September

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

Average high: 83°F
Average low: 59°F
Rainy days: ~1 per month
Total precipitation: 0.3 in
Warmest recorded: 116°F
Coldest recorded: 52°F

Expect September days in San Jose, California to top out around 83°F and cool to about 59°F overnight, with roughly 1 days of measurable rain across the month. In recent years September has ranged from 52°F to 116°F.

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