August weather in St. Helena, CA
The average temperature in St. Helena in August is 72.3°F (55.7°F–88.8°F). Average precipitation: 0.04 inches.
August is a summer month in St. Helena, and is warmer than the annual average of 61°F. Daily temperatures swing about 33.1°F between overnight low and afternoon high. Expect about 0 days with precipitation. Daylight averages about 13h 30m. For travel, August is hot.
Avg High
88.8°F
Avg Low
55.7°F
Precipitation
0.04 in
Daylight
13h 30m
August records in St. Helena
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| August 1 | 111.0°F (1993) | 41.0°F (1923) | 0.00 in (1908) |
| August 2 | 109.0°F (1946) | 39.9°F (1919) | 0.00 in (1908) |
| August 3 | 108.0°F (1969) | 42.1°F (1923) | 0.00 in (1908) |
| August 4 | 107.1°F (1997) | 43.0°F (1925) | 0.00 in (1908) |
| August 5 | 107.1°F (1997) | 39.9°F (1924) | 0.10 in (1974) |
| August 6 | 108.0°F (1913) | 42.1°F (1924) | 0.01 in (2014) |
| August 7 | 108.0°F (1981) | 42.1°F (1923) | 0.01 in (1921) |
| August 8 | 106.0°F (1990) | 39.9°F (1924) | 0.02 in (1963) |
| August 9 | 105.1°F (1970) | 32.0°F (1978) | 0.04 in (1962) |
| August 10 | 108.0°F (1996) | 43.0°F (1924) | 0.01 in (1936) |
| August 11 | 109.9°F (1996) | 32.0°F (2000) | 0.67 in (1965) |
| August 12 | 107.1°F (1996) | 41.0°F (1911) | 0.15 in (1965) |
| August 13 | 105.1°F (1933) | 41.0°F (1911) | 0.09 in (1991) |
| August 14 | 109.0°F (1996) | 42.1°F (1918) | 0.52 in (1916) |
| August 15 | 106.0°F (1920) | 39.9°F (1911) | 0.24 in (1976) |
| August 16 | 105.1°F (2015) | 41.0°F (1924) | 0.02 in (1941) |
| August 17 | 108.0°F (1939) | 41.0°F (1922) | 0.01 in (1941) |
| August 18 | 107.1°F (1950) | 41.0°F (1922) | 0.35 in (1976) |
| August 19 | 111.0°F (1950) | 39.9°F (1928) | 0.25 in (1968) |
| August 20 | 106.0°F (1950) | 41.0°F (1910) | 0.73 in (1997) |
| August 21 | 102.9°F (1910) | 39.9°F (1910) | 0.41 in (1968) |
| August 22 | 104.0°F (1931) | 39.9°F (1921) | 0.20 in (2003) |
| August 23 | 108.0°F (1913) | 39.9°F (1908) | 0.00 in (1908) |
| August 24 | 109.9°F (1931) | 41.0°F (1930) | 0.00 in (1908) |
| August 25 | 107.1°F (1988) | 39.9°F (1938) | 0.10 in (1926) |
| August 26 | 107.1°F (1944) | 39.9°F (1938) | 0.25 in (1935) |
| August 27 | 109.0°F (2017) | 37.9°F (1942) | 0.09 in (1949) |
| August 28 | 111.9°F (1915) | 39.9°F (1921) | 0.46 in (1954) |
| August 29 | 107.1°F (1918) | 42.1°F (1922) | 0.13 in (1953) |
| August 30 | 106.0°F (1915) | 39.9°F (1957) | 0.31 in (1966) |
| August 31 | 107.1°F (1955) | 39.9°F (1921) | 0.01 in (1966) |