Average monthly snow and rainfall in St. Helena (CA)

The mean monthly precipitation over the year in St. Helena (California), including rain, snow, hail.

• A lot of rain (rainy season) falls in the months: January, February, March and December.
• St. Helena has dry periods in May, June, July, August and September.
• On average, December is the wettest month with 175 mm of precipitation.
• On average, August is the driest month with 0 mm of precipitation.
• The average amount of annual precipitation is 800 mm.