In September, San Jose typically sees daytime highs of 28.1°C and overnight lows around 12.6°C. Compared to the annual average high of 21.3°C, September runs +6.8°C.
September in San Jose averages a daytime high of 28.1°C and an overnight low of 12.6°C.
September runs +6.8°C compared to San Jose's annual average high of 21.3°C, ranking #3 of 12 months by warmth.
Plan for daytime highs near 28.1°C and cooler evenings around 12.6°C.