The highest day temperature in December 2023 was 64°F. The lowest night temperature was 36°F. The average values for day and night temperatures during December were 58.7°F и 49.1°F respectivly.

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

Precipitation total in December for Napa is 1.6 in. It makes december the most rainy month of the year.

The average wind speed in December is 3.7 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 Napa in December is 5.5 hours.