In December, Walnut Creek typically sees daytime highs of 12.2°C and overnight lows around 3.9°C. Compared to the annual average high of 20.0°C, December runs -7.8°C.
December in Walnut Creek averages a daytime high of 12.2°C and an overnight low of 3.9°C.
December runs -7.8°C compared to Walnut Creek's annual average high of 20.0°C, ranking #11 of 12 months by warmth.
Plan for daytime highs near 12.2°C and cooler evenings around 3.9°C.