May weather in St. Helena, CA
The average temperature in St. Helena in May is 64.3°F (50.5°F–78.1°F). Average precipitation: 1.31 inches.
May is a spring month in St. Helena, and is warmer than the annual average of 61°F. Daily temperatures swing about 27.6°F between overnight low and afternoon high. Expect about 3 days with precipitation. Daylight averages about 14h 6m. For travel, May is one of the best months of the year to visit.
Avg High
78.1°F
Avg Low
50.5°F
Precipitation
1.31 in
Daylight
14h 6m
May records in St. Helena
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| May 1 | 98.1°F (1996) | 34.0°F (1967) | 1.71 in (1995) |
| May 2 | 95.0°F (1996) | 33.1°F (1921) | 0.82 in (1957) |
| May 3 | 97.0°F (2017) | 32.0°F (1950) | 1.13 in (2003) |
| May 4 | 97.0°F (2017) | 32.0°F (1921) | 0.56 in (1940) |
| May 5 | 100.0°F (1987) | 30.9°F (1933) | 0.70 in (2009) |
| May 6 | 102.0°F (1987) | 33.1°F (1964) | 0.34 in (1988) |
| May 7 | 100.9°F (1987) | 32.0°F (1916) | 0.92 in (1933) |
| May 8 | 97.0°F (2020) | 34.0°F (1926) | 1.06 in (1915) |
| May 9 | 98.1°F (1931) | 33.1°F (1918) | 1.19 in (1915) |
| May 10 | 100.0°F (1934) | 34.0°F (1933) | 0.71 in (2004) |
| May 11 | 97.0°F (1934) | 35.1°F (1933) | 0.47 in (2020) |
| May 12 | 102.9°F (1976) | 36.0°F (1967) | 1.42 in (1925) |
| May 13 | 100.0°F (1927) | 36.0°F (1943) | 0.63 in (1941) |
| May 14 | 98.1°F (1922) | 36.0°F (1918) | 0.55 in (2000) |
| May 15 | 99.0°F (1927) | 34.0°F (1908) | 0.39 in (1942) |
| May 16 | 98.1°F (1970) | 33.1°F (1908) | 1.91 in (1996) |
| May 17 | 99.0°F (1997) | 36.0°F (1908) | 0.67 in (1944) |
| May 18 | 104.0°F (1997) | 33.1°F (1974) | 2.00 in (2005) |
| May 19 | 100.9°F (1997) | 35.1°F (1918) | 0.72 in (1925) |
| May 20 | 99.0°F (1947) | 37.0°F (1974) | 0.70 in (2002) |
| May 21 | 99.0°F (1935) | 35.1°F (1922) | 0.82 in (1939) |
| May 22 | 99.0°F (2000) | 30.9°F (1979) | 0.64 in (1996) |
| May 23 | 100.9°F (1943) | 30.0°F (1979) | 0.68 in (1960) |
| May 24 | 99.0°F (2022) | 32.0°F (1979) | 1.23 in (1931) |
| May 25 | 100.0°F (1951) | 36.0°F (1923) | 1.02 in (1942) |
| May 26 | 100.9°F (2020) | 33.1°F (1918) | 0.52 in (1934) |
| May 27 | 105.1°F (1919) | 30.9°F (1918) | 1.20 in (2010) |
| May 28 | 104.0°F (1984) | 37.0°F (1911) | 0.88 in (1998) |
| May 29 | 106.0°F (1910) | 37.9°F (1927) | 1.24 in (1998) |
| May 30 | 107.1°F (1919) | 35.1°F (1918) | 0.71 in (1940) |
| May 31 | 106.0°F (1919) | 35.1°F (1918) | 0.17 in (1925) |