The highest day temperature in December 2025 was 51°F. The lowest night temperature was 19°F. The average values for day and night temperatures during December were 40.4°F и 32.6°F respectivly.

The average sea surface temperature in December 2025 for St Gallen was 45.1°F. The maximum and minimum values were 43.2°F and 47.8°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 Gallen is 3.8 in.

The average wind speed in December is 4.7 mph. This value is relatively stable throughout the year.

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 Gallen in December is 4.6 hours.