The highest day temperature in December 2024 was 55°F. The lowest night temperature was 30°F. The average values for day and night temperatures during December were 48.3°F и 37.8°F respectivly.

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

Precipitation total in December for Siena is 1.7 in.

The average wind speed in December is 4.8 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 Siena in December is 5.2 hours.