In January, Diamond Bar typically sees daytime highs of 17.3°C and overnight lows around 5.3°C. Compared to the annual average high of 24.1°C, January runs -6.9°C.
January in Diamond Bar averages a daytime high of 17.3°C and an overnight low of 5.3°C.
January runs -6.9°C compared to Diamond Bar's annual average high of 24.1°C, ranking #12 of 12 months by warmth.
Plan for daytime highs near 17.3°C and cooler evenings around 5.3°C.