In December, Castle Rock typically sees daytime highs of 6.8°C and overnight lows around -8.9°C. Compared to the annual average high of 16.8°C, December runs -9.9°C.
December in Castle Rock averages a daytime high of 6.8°C and an overnight low of -8.9°C.
December runs -9.9°C compared to Castle Rock's annual average high of 16.8°C, ranking #11 of 12 months by warmth.
Plan for daytime highs near 6.8°C and cooler evenings around -8.9°C.