Temperature for December
In Harlingen, TX during December the average high temperature is 72.5°F. The hottest day on record was December 7, 1996 when the temperature hit 91.4°F.
Precipitation for December
In December the average monthly rainfall in Harlingen, TX is 0.29 inches with rain usually falling on between 6 and 7 days. 1943 was the driest December with only 0.00 inches of rain falling, and 2009 was the wettest December with 4.33 inches of rain. The wettest single day in December was 24 December 2006 when 2.43 inches of rain fell.
In December it usually snows on between 0 and 1 days. In December there have been some years when thunderstorms have occurred, although there are other years when there hasn't been a thunderstorm in December.