The highest day temperature in December 2025 was 55°F. The lowest night temperature was 16°F. The average values for day and night temperatures during December were 35.3°F и 29.5°F respectivly.

The average sea surface temperature in December 2025 for Chatham was 43.1°F. The maximum and minimum values were 39.2°F and 47.4°F respectively.

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

Precipitation total in December for Chatham is 1.2 in. It makes december one of the most rainy months of the year.

The average wind speed in December is 14.9 mph. It makes December the most windy month of the year for Chatham.

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 Chatham in December is 4.3 hours.