Temperature for December
In Portland, ME during December the average high temperature is 39.2°F. The hottest day on record was December 7, 2001 when the temperature recorded was 71.1°F.

In Portland, ME during December the average high temperature is 39.2°F. The hottest day on record was December 7, 2001 when the temperature recorded was 71.1°F.
In December the average monthly rainfall in Portland, ME is 4.26 inches with rain usually falling on between 8 and 9 days. 1980 was the driest December with only 1.08 inches of rain falling, and 1983 was the wettest December with 10.26 inches of rain. The wettest single day in December was 4 December 1990 when 3.02 inches of rain fell.
In December it usually snows on between 9 and 10 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.