If you come to the Napa Valley in the winter, early December may become your favorite time to visit as it is the least crowded time the of the year.
In December, the average temperature in Calistoga is 48 degrees, with an average high of 59, and an average low of 36 degrees. The average rainfall in Calistoga for December is 7.88 inches. Usually the days of wet weather are brief, followed by crisp and clear blue skies. By crisp, of course, we are talking of California standards, which means that daytime temperatures usually exceed 50, and often reach into the 60’s.
In the town of Napa, the average temperature in December is 48 degrees, while the average high is 56 degrees and the average low temperature is 38 degrees. The average rainfall for December is 3.9 inches.