In December, Rockville typically sees daytime highs of 7.2°C and overnight lows around -3.0°C. Compared to the annual average high of 18.5°C, December runs -11.4°C.
December in Rockville averages a daytime high of 7.2°C and an overnight low of -3.0°C.
December runs -11.4°C compared to Rockville's annual average high of 18.5°C, ranking #10 of 12 months by warmth.
Plan for daytime highs near 7.2°C and cooler evenings around -3.0°C.