In September, Vacaville typically sees daytime highs of 30.6°C and overnight lows around 12.6°C. Compared to the annual average high of 23.0°C, September runs +7.6°C.
September in Vacaville averages a daytime high of 30.6°C and an overnight low of 12.6°C.
September runs +7.6°C compared to Vacaville's annual average high of 23.0°C, ranking #3 of 12 months by warmth.
Plan for daytime highs near 30.6°C and cooler evenings around 12.6°C.