The highest day temperature in December 2025 was 55°F. The lowest night temperature was -6°F. The average values for day and night temperatures during December were 27.2°F и 18.9°F respectivly.

The average sea surface temperature in December 2025 for Mount Desert Island was 42.4°F. The maximum and minimum values were 38.8°F and 46.2°F respectively.

Most of the days in December are gloomy but you can also expect sunny days.

Precipitation total in December for Mount Desert Island is 1.5 in. It makes december the most rainy month of the year.

The average wind speed in December is 10.7 mph. It makes December the most windy month of the year for Mount Desert Island.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Mount Desert Island in December is 4.4 hours.