May weather in Helena, MT
The average temperature in Helena in May is 53.9°F (41.5°F–66.4°F). Average precipitation: 1.95 inches.
May is a spring month in Helena, and is warmer than the annual average of 45.5°F. Daily temperatures swing about 24.9°F between overnight low and afternoon high. Expect about 11 days with precipitation. Daylight averages about 14h 49m. For travel, May is a comfortable month to visit.
Avg High
66.4°F
Avg Low
41.5°F
Precipitation
1.95 in
Snow
0.1 in
May records in Helena
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| May 1 | 84.0°F (2023) | 19.9°F (1954) | 0.37 in (1964) |
| May 2 | 86.0°F (1947) | 17.1°F (1954) | 0.77 in (1950) |
| May 3 | 84.0°F (1966) | 23.0°F (1967) | 2.06 in (1964) |
| May 4 | 87.1°F (1966) | 21.9°F (1996) | 0.88 in (1993) |
| May 5 | 87.1°F (2017) | 19.9°F (1996) | 0.39 in (1946) |
| May 6 | 90.0°F (1966) | 23.0°F (1996) | 0.75 in (1958) |
| May 7 | 86.0°F (1987) | 23.0°F (2010) | 0.51 in (1948) |
| May 8 | 84.9°F (1987) | 23.0°F (1997) | 1.01 in (1948) |
| May 9 | 84.0°F (1987) | 24.1°F (2002) | 0.77 in (1983) |
| May 10 | 88.0°F (1940) | 23.0°F (1946) | 1.11 in (1967) |
| May 11 | 87.1°F (1993) | 25.0°F (1968) | 0.88 in (1995) |
| May 12 | 91.9°F (2001) | 21.9°F (1943) | 0.94 in (1995) |
| May 13 | 89.1°F (2001) | 23.0°F (1983) | 1.32 in (1962) |
| May 14 | 87.1°F (1978) | 25.0°F (1995) | 1.07 in (1977) |
| May 15 | 90.0°F (1939) | 26.1°F (1943) | 0.44 in (1962) |
| May 16 | 91.0°F (1988) | 28.0°F (1986) | 0.86 in (2015) |
| May 17 | 90.0°F (2006) | 26.1°F (1943) | 0.84 in (2017) |
| May 18 | 91.0°F (2006) | 28.0°F (1942) | 1.10 in (1944) |
| May 19 | 90.0°F (1954) | 24.1°F (1997) | 0.75 in (2020) |
| May 20 | 90.0°F (2002) | 28.0°F (1959) | 1.78 in (1957) |
| May 21 | 89.1°F (1980) | 27.0°F (1953) | 1.93 in (1981) |
| May 22 | 86.0°F (2001) | 29.1°F (2021) | 0.96 in (2002) |
| May 23 | 89.1°F (2001) | 26.1°F (1944) | 0.71 in (2008) |
| May 24 | 93.0°F (2001) | 28.9°F (1944) | 1.56 in (1953) |
| May 25 | 89.1°F (2003) | 25.0°F (1950) | 1.19 in (1980) |
| May 26 | 88.0°F (1966) | 28.9°F (1975) | 0.96 in (2019) |
| May 27 | 90.0°F (1986) | 27.0°F (1995) | 1.16 in (2006) |
| May 28 | 91.9°F (2003) | 28.0°F (1947) | 1.08 in (2001) |
| May 29 | 91.0°F (1986) | 27.0°F (1951) | 0.58 in (2022) |
| May 30 | 91.9°F (1986) | 28.9°F (1977) | 0.82 in (1988) |
| May 31 | 91.0°F (2025) | 30.9°F (1982) | 0.95 in (2018) |