St. Helena, CA has a Mediterranean climate with mild winters and hot, dry summers. The average daily high temperature during the summer months is in the 70s and 80s Fahrenheit, while winter temperatures rarely dip below the mid-50s. Precipitation is low throughout the year, with an annual average of around 20 inches of rain annually. During the summer months, humidity can become quite high due to its proximity to the Pacific Ocean.
St. Helena, California gets 37 inches of rain, on average, per year. The US average is 38 inches of rain per year.
St. Helena averages 0 inches of snow per year. The US average is 28 inches of snow per year.
On average, there are 263 sunny days per year in St. Helena. The US average is 205 sunny days.
St. Helena gets some kind of precipitation, on average, 71 days per year. Precipitation is rain, snow, sleet, or hail that falls to the ground. In order for precipitation to be counted you have to get at least .01 inches on the ground to measure.
Weather Highlights
Summer High: the July high is around 89 degrees
Winter Low: the January low is 38
Rain: averages 37 inches of rain a year
Snow: averages 0 inches of snow a year