In December, Harlingen typically sees daytime highs of 22.1°C and overnight lows around 11.0°C. Compared to the annual average high of 28.5°C, December runs -6.4°C.
December in Harlingen averages a daytime high of 22.1°C and an overnight low of 11.0°C.
December runs -6.4°C compared to Harlingen's annual average high of 28.5°C, ranking #11 of 12 months by warmth.
Plan for daytime highs near 22.1°C and cooler evenings around 11.0°C.