In December, San Ramon typically sees daytime highs of 12.0°C and overnight lows around 3.7°C. Compared to the annual average high of 20.6°C, December runs -8.6°C.
December in San Ramon averages a daytime high of 12.0°C and an overnight low of 3.7°C.
December runs -8.6°C compared to San Ramon's annual average high of 20.6°C, ranking #11 of 12 months by warmth.
Plan for daytime highs near 12.0°C and cooler evenings around 3.7°C.