Helena Weather in May
Average highs run from 62°F on May 1 to 70°F on May 31, and lows from 37°F to 46°F. Normal precipitation for the month is 1.95 in over about 11 wet days.
May day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
May at a glance
- Average high
- 66°F
- Average low
- 42°F
- Precipitation
- 1.95 in
- Snowfall
- 0.1 in
- Record high
- 93°FMay 24, 2001
- Record low
- 17°FMay 2, 1954
- Chance of a freeze
- 84%
- Daylight
- 14 h 25 min to 15 h 34 min
- Cloud cover
- 69%
- Humidity
- 66%
- Dew point
- 34°F
- Wind
- 6.3 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.
| Date | Normal high | Normal low | Record high | Record low | Chance wet | Chance of snow |
|---|---|---|---|---|---|---|
| May 1 | 62°F | 37°F | 84°F 2023 | 20°F 1954 | 31% | 4% |
| May 2 | 62°F | 37°F | 86°F 1947 | 17°F 1954 | 31% | 4% |
| May 3 | 62°F | 37°F | 84°F 1966 | 23°F 1967 | 31% | 3% |
| May 4 | 63°F | 38°F | 87°F 1966 | 22°F 1996 | 32% | 3% |
| May 5 | 63°F | 38°F | 87°F 2017 | 20°F 1996 | 32% | 3% |
| May 6 | 63°F | 38°F | 90°F 1966 | 23°F 1996 | 32% | 3% |
| May 7 | 64°F | 39°F | 86°F 1987 | 23°F 2010 | 33% | 3% |
| May 8 | 64°F | 39°F | 85°F 1987 | 23°F 1997 | 33% | 2% |
| May 9 | 64°F | 39°F | 84°F 1987 | 24°F 2002 | 34% | 2% |
| May 10 | 65°F | 40°F | 88°F 1940 | 23°F 1946 | 34% | 2% |
| May 11 | 65°F | 40°F | 87°F 1993 | 25°F 1968 | 34% | 2% |
| May 12 | 65°F | 40°F | 92°F 2001 | 22°F 1943 | 35% | 2% |
| May 13 | 66°F | 41°F | 89°F 2001 | 23°F 1983 | 35% | 2% |
| May 14 | 66°F | 41°F | 87°F 1978 | 25°F 1995 | 36% | 2% |
| May 15 | 66°F | 41°F | 90°F 1939 | 26°F 1943 | 36% | 1% |
| May 16 | 67°F | 42°F | 91°F 1988 | 28°F 1986 | 37% | 1% |
| May 17 | 67°F | 42°F | 90°F 2006 | 26°F 1943 | 37% | 1% |
| May 18 | 67°F | 42°F | 91°F 2006 | 28°F 1942 | 37% | 1% |
| May 19 | 68°F | 43°F | 90°F 1954 | 24°F 1997 | 38% | 1% |
| May 20 | 68°F | 43°F | 90°F 2002 | 28°F 1959 | 38% | 1% |
| May 21 | 68°F | 43°F | 89°F 1980 | 27°F 1953 | 39% | 1% |
| May 22 | 68°F | 44°F | 86°F 2001 | 29°F 2021 | 39% | 1% |
| May 23 | 69°F | 44°F | 89°F 2001 | 26°F 1944 | 39% | 1% |
| May 24 | 69°F | 44°F | 93°F 2001 | 29°F 1944 | 40% | 1% |
| May 25 | 69°F | 44°F | 89°F 2003 | 25°F 1950 | 40% | 1% |
| May 26 | 69°F | 45°F | 88°F 1966 | 29°F 1975 | 40% | 1% |
| May 27 | 70°F | 45°F | 90°F 1986 | 27°F 1995 | 41% | 0% |
| May 28 | 70°F | 45°F | 92°F 2003 | 28°F 1947 | 41% | 0% |
| May 29 | 70°F | 45°F | 91°F 1986 | 27°F 1951 | 41% | 0% |
| May 30 | 70°F | 46°F | 92°F 1986 | 29°F 1977 | 41% | 0% |
| May 31 | 70°F | 46°F | 91°F 2025 | 31°F 1982 | 41% | 0% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (MDT).
- May 1
- sunrise 6:13 AM, sunset 8:38 PM
- May 31
- sunrise 5:39 AM, sunset 9:13 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USW00024144 (Helena Rgnl AP), public domain. Records: NOAA GHCN-Daily, station USW00024144, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.