In December, Flagstaff typically sees daytime highs of 6.9°C and overnight lows around -7.7°C. Compared to the annual average high of 16.9°C, December runs -9.9°C.
December in Flagstaff averages a daytime high of 6.9°C and an overnight low of -7.7°C.
December runs -9.9°C compared to Flagstaff's annual average high of 16.9°C, ranking #11 of 12 months by warmth.
Plan for daytime highs near 6.9°C and cooler evenings around -7.7°C.