Helena Weather in May
Average highs run from 74°F on May 1 to 85°F on May 31, and lows from 49°F to 62°F. Normal precipitation for the month is 4.37 in over about 9 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
- 80°F
- Average low
- 56°F
- Precipitation
- 4.37 in
- Record high
- 104°FMay 30, 1985
- Record low
- 28°FMay 1, 1909
- Chance of a freeze
- 2%
- Days of 90°F or more
- 4.7
- Daylight
- 13 h 42 min to 14 h 28 min
- Cloud cover
- 56%
- Humidity
- 64%
- Dew point
- 54°F
- Wind
- 11.6 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 | 74°F | 49°F | 95°F 1948 | 28°F 1909 | 29% | 0% |
| May 2 | 75°F | 50°F | 91°F 2020 | 32°F 1907 | 29% | 0% |
| May 3 | 75°F | 50°F | 99°F 1950 | 31°F 1907 | 29% | 0% |
| May 4 | 75°F | 51°F | 93°F 1909 | 37°F 1954 | 29% | 0% |
| May 5 | 75°F | 51°F | 100°F 2014 | 36°F 1907 | 29% | 0% |
| May 6 | 76°F | 52°F | 99°F 2014 | 31°F 1908 | 29% | 0% |
| May 7 | 76°F | 52°F | 98°F 2014 | 35°F 1907 | 29% | 0% |
| May 8 | 77°F | 52°F | 98°F 1918 | 36°F 1938 | 29% | 0% |
| May 9 | 77°F | 53°F | 99°F 2011 | 34°F 1909 | 30% | 0% |
| May 10 | 77°F | 53°F | 101°F 1967 | 35°F 1909 | 30% | 0% |
| May 11 | 78°F | 54°F | 96°F 1963 | 37°F 1946 | 30% | 0% |
| May 12 | 78°F | 54°F | 96°F 2000 | 40°F 1946 | 30% | 0% |
| May 13 | 78°F | 55°F | 98°F 1956 | 37°F 1966 | 30% | 0% |
| May 14 | 79°F | 55°F | 92°F 1952 | 38°F 1953 | 30% | 0% |
| May 15 | 79°F | 55°F | 95°F 2018 | 33°F 1907 | 30% | 0% |
| May 16 | 79°F | 56°F | 94°F 1931 | 41°F 1907 | 30% | 0% |
| May 17 | 80°F | 56°F | 95°F 1956 | 40°F 1945 | 30% | 0% |
| May 18 | 80°F | 57°F | 99°F 1956 | 37°F 1894 | 30% | 0% |
| May 19 | 81°F | 57°F | 96°F 1937 | 44°F 1904 | 30% | 0% |
| May 20 | 81°F | 58°F | 100°F 2006 | 41°F 1894 | 30% | 0% |
| May 21 | 81°F | 58°F | 101°F 2006 | 42°F 1915 | 30% | 0% |
| May 22 | 82°F | 58°F | 98°F 2005 | 38°F 1931 | 30% | 0% |
| May 23 | 82°F | 59°F | 100°F 1996 | 38°F 1917 | 30% | 0% |
| May 24 | 83°F | 59°F | 100°F 2000 | 41°F 1935 | 30% | 0% |
| May 25 | 83°F | 60°F | 97°F 1911 | 42°F 2002 | 30% | 0% |
| May 26 | 83°F | 60°F | 101°F 2006 | 45°F 1992 | 30% | 0% |
| May 27 | 84°F | 60°F | 100°F 1896 | 36°F 1907 | 30% | 0% |
| May 28 | 84°F | 61°F | 97°F 1895 | 43°F 1907 | 30% | 0% |
| May 29 | 84°F | 61°F | 100°F 1913 | 39°F 1947 | 30% | 0% |
| May 30 | 85°F | 61°F | 104°F 1985 | 47°F 1947 | 30% | 0% |
| May 31 | 85°F | 62°F | 102°F 1913 | 40°F 1972 | 29% | 0% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (CDT).
- May 1
- sunrise 6:39 AM, sunset 8:21 PM
- May 31
- sunrise 6:17 AM, sunset 8:45 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00344019 (Helena 1 Sse), public domain. Records: NOAA GHCN-Daily, station USC00342912, 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.