In December, South San Francisco typically sees daytime highs of 13.3°C and overnight lows around 5.7°C. Compared to the annual average high of 17.7°C, December runs -4.4°C.
December in South San Francisco averages a daytime high of 13.3°C and an overnight low of 5.7°C.
December runs -4.4°C compared to South San Francisco's annual average high of 17.7°C, ranking #11 of 12 months by warmth.
Plan for daytime highs near 13.3°C and cooler evenings around 5.7°C.