The highest day temperature in December 2025 was 57°F. The lowest night temperature was 27°F. The average values for day and night temperatures during December were 47.9°F и 41.4°F respectivly.

The average sea surface temperature in December 2025 for St Constantine and Helena was 54.1°F. The maximum and minimum values were 49.8°F and 60.2°F respectively.

You can expect various weather conditions during December. Be ready for sunny, cloudy or even gloomy days.

Precipitation total in December for St Constantine and Helena is 1.1 in. It makes december one of the least rainy months of the year.

The average wind speed in December is 11.2 mph. It makes December one of the most windy months of the year for St Constantine and Helena.

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 St Constantine and Helena in December is 4.8 hours.