Napa Temperatures: Averages by Month
The numbers here tell you how hot and cold the weather usually is in Napa, California during each month of the year.
The average high and low temperatures are listed below for Napa, in both degrees Fahrenheit and Celsius.
Maximums and minimums are only part of the temperature picture. To fill in the rest, there's information on how many days a month get above or below a given temperature.
To find out how often it rises over 70, 80 or 90 °F monthly and annually in the heart of California's wine country, scroll down farther. There are also counts of nights with cool temperatures.
All the numbers are averages, based on climate data gathered from 1981 to 2010.
|High °F||Low °F||High °C||Low °C|
Days of Hot Weather in Napa
Napa's ideal grape-growing weather is also pleasant for people. Summer days usually warm up to the 70s or 80s Fahrenheit, as does most of May to October.
Hotter weather occurs sporadically during those months, with 25 days reaching 90 and three of those on average making it to 100 °F (38 °C).
How Often Napa Has Cool Temperatures
Most nights at Napa never get colder than 40 °F. From November to February, it averages 12 nights with frost, but the next day always warms up to at least 40 degrees and usually 50 (10 °C). Only about once a decade does really cold weather descend here, when the temperature drops to 20 °F (-8 °C).
National Climatic Data Center. NOAA's 1981-2010 Climate Normals.