St. Helena, CA
Climate overview — based on NOAA 1991-2020 normals from SAINT HELENA, CA US.
Year-round temperatures (°F)
Climate summary
St. Helena has an annual average temperature of 61°F with about 34 inches of precipitation per year. The warmest month is August (average high 88.8°F), and the coldest is December (average low 39.6°F). December is typically the wettest month (7.18 in) and July the driest (0.01 in).
Best time to visit St. Helena
Full guide →Climate change signal
All-time records →34 of 366 (9.3%) of St. Helena's all-time daily heat records have been set since 2015. If records were spread evenly across the station's history, only about 5% would fall in any given decade.
| 1900s | 5 | |
| 1910s | 48 | |
| 1920s | 51 | |
| 1930s | 62 | |
| 1940s | 17 | |
| 1950s | 27 | |
| 1960s | 26 | |
| 1970s | 24 | |
| 1980s | 19 | |
| 1990s | 30 | |
| 2000s | 15 | |
| 2010s | 29 | |
| 2020s | 13 |
Bars: number of all-time daily heat records still standing that were set in each decade.
Monthly averages
| Month | Avg High | Avg Low | Avg Temp | Precipitation | Snow | Rainy days |
|---|---|---|---|---|---|---|
| January | 58.8°F | 40.2°F | 49.5°F | 6.47 in | — | 13 |
| February | 62.5°F | 41.9°F | 52.2°F | 6.71 in | — | 11 |
| March | 66.8°F | 43.9°F | 55.4°F | 4.98 in | — | 10 |
| April | 71.8°F | 46.3°F | 59.0°F | 1.97 in | — | 6 |
| May | 78.1°F | 50.5°F | 64.3°F | 1.31 in | — | 3 |
| June | 85.4°F | 54.2°F | 69.8°F | 0.35 in | — | 1 |
| July | 88.7°F | 56.0°F | 72.4°F | 0.01 in | — | 0 |
| August | 88.8°F | 55.7°F | 72.3°F | 0.04 in | — | 0 |
| September | 86.6°F | 53.8°F | 70.2°F | 0.06 in | — | 1 |
| October | 78.1°F | 49.4°F | 63.7°F | 1.65 in | — | 3 |
| November | 65.8°F | 43.7°F | 54.7°F | 3.24 in | — | 8 |
| December | 58.3°F | 39.6°F | 48.9°F | 7.18 in | — | 13 |
Climate twins of St. Helena
Why these? →The most climatically similar US cities at least 140 miles away (by monthly temperature + precipitation pattern).