St. Helena (CA) Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit St. Helena.
Climate overview of St. Helena
Temperatures in St. Helena, California, United States of America, vary greatly throughout the year. July is the hottest month at 32°C (90°F), while December is the coldest at 14°C (57°F).
The city receives around 800 mm (31 in) of rainfall per year. It experiences a distinct dry season from May to September, with very warm summers and mild winters. December is the wettest month and August the driest. Sunshine peaks in May, when the city sees around 10.3 hours of sunshine per day.
St. Helena Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in St. Helena - and find the best time to visit.
Monthly Temperature in St. Helena
The climate in St. Helena is known for significant temperature differences throughout the year, making the weather dynamic. On average, daytime temperatures range from a very warm 32°C (90°F) in July to a moderate 14°C (57°F) in December.
Nighttime temperatures range from 13°C (55°F) in July to 4°C (39°F) in December.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in St. Helena
Generally, St. Helena receives mid-range precipitation levels, with 800 mm (31 in) annually. The seasons in St. Helena bring significant changes in precipitation. The wettest month, December, receives heavy rainfall, with an average of 175 mm (6.9 in) of precipitation. This rainfall is distributed across 14 rainy days.
In contrast, the driest month, August, experiences much less rainfall, totaling 0 mm (0 in) over 0 rainy days. These distinct seasonal differences provide diverse experiences throughout the year. For more details, please visit our St. Helena Precipitation page.
The mean monthly precipitation over the year, including rain, hail, and snow
The average number of days each month with precipitation
Sunshine Hours in St. Helena
In St. Helena, summer days are longer and more sunny, with daily sunshine hours peaking at 10.3 hours in May. As the darker season arrives, the brightness of the sun becomes less. December sees a soft sun for only 5.3 hours per average day.
Visit our detailed sunshine hours page for more information.
Monthly hours of sunshine
Daily hours of sunshine
Daily percentage of sunshine
Best Time to Visit St. Helena
Monthly ratings reflect general weather comfort, based on daytime temperature and rainfall. Swimming and winter conditions are highlighted separately where relevant.
- Best overall: April, May and October
- Warmest weather: July, August and September
- Most sunshine: April, May, June and July
- Fewest rainy days: June, July, August and September
- Wettest months: January, February, March, November and December, when rainfall is highest.
- Seasonal pattern: A distinct dry season from May to September, with very warm summers and mild winters
Frequently asked questions about the climate in St. Helena
What is the best time to visit St. Helena?
April, May and October typically offer the most optimal weather in St. Helena. In contrast, January, February and December tend to have less optimal conditions. St. Helena has a distinct dry season from May to September, with very warm summers and mild winters.
What temperatures can I expect in St. Helena?
Daytime highs range from 14°C (57°F) in December to 32°C (90°F) in July. Nighttime lows range from 4°C (39°F) to 13°C (55°F). Temperatures vary considerably through the year.
How much rain does St. Helena get?
Annual rainfall is around 800 mm (31 in). December is the wettest month with 175 mm (6.9 in), while August is the driest with 0 mm (0 in).
How sunny is St. Helena?
St. Helena receives around 3,042 hours of sunshine per year. May is the sunniest month with 310 hours, while December is the cloudiest with just 160 hours. Overall, St. Helena enjoys abundant sunshine.
St. Helena 3-Day Forecast
St. Helena (CA) 3-Day Forecast
St. Helena on the map
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