In September, Gilroy typically sees daytime highs of 27.7°C and overnight lows around 11.2°C. Compared to the annual average high of 21.3°C, September runs +6.3°C.
September in Gilroy averages a daytime high of 27.7°C and an overnight low of 11.2°C.
September runs +6.3°C compared to Gilroy's annual average high of 21.3°C, ranking #3 of 12 months by warmth.
Plan for daytime highs near 27.7°C and cooler evenings around 11.2°C.