In December, Boise typically sees daytime highs of 2.3°C and overnight lows around -5.5°C. Compared to the annual average high of 15.8°C, December runs -13.5°C.
December in Boise averages a daytime high of 2.3°C and an overnight low of -5.5°C.
December runs -13.5°C compared to Boise's annual average high of 15.8°C, ranking #11 of 12 months by warmth.
Plan for daytime highs near 2.3°C and cooler evenings around -5.5°C.