Lewistown Weather in May
Average highs run from 58°F on May 1 to 67°F on May 31, and lows from 32°F to 42°F. Normal precipitation for the month is 2.88 in over about 14 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
- 63°F
- Average low
- 37°F
- Precipitation
- 2.88 in
- Snowfall
- 3.1 in
- Record high
- 98°FMay 14, 1931
- Record low
- 11°FMay 6, 1929
- Chance of a freeze
- 99%
- Daylight
- 14 h 27 min to 15 h 38 min
- Cloud cover
- 67%
- Humidity
- 63%
- Dew point
- 35°F
- Wind
- 10.3 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 | 58°F | 32°F | 82°F 2000 | 13°F 2013 | 41% | 12% |
| May 2 | 58°F | 33°F | 86°F 1985 | 14°F 1954 | 42% | 11% |
| May 3 | 58°F | 33°F | 82°F 1918 | 16°F 1954 | 42% | 11% |
| May 4 | 59°F | 33°F | 84°F 1918 | 16°F 1967 | 42% | 11% |
| May 5 | 59°F | 34°F | 85°F 1934 | 21°F 1913 | 42% | 10% |
| May 6 | 59°F | 34°F | 85°F 1928 | 11°F 1929 | 42% | 10% |
| May 7 | 60°F | 34°F | 89°F 1908 | 23°F 1929 | 43% | 9% |
| May 8 | 60°F | 35°F | 85°F 1928 | 19°F 1929 | 43% | 9% |
| May 9 | 60°F | 35°F | 84°F 1906 | 16°F 2002 | 43% | 9% |
| May 10 | 61°F | 35°F | 88°F 1906 | 11°F 1946 | 43% | 8% |
| May 11 | 61°F | 36°F | 86°F 1993 | 19°F 1953 | 44% | 8% |
| May 12 | 62°F | 36°F | 88°F 2001 | 19°F 1916 | 44% | 7% |
| May 13 | 62°F | 36°F | 88°F 1903 | 15°F 1953 | 44% | 7% |
| May 14 | 62°F | 37°F | 98°F 1931 | 25°F 1916 | 44% | 7% |
| May 15 | 63°F | 37°F | 87°F 1931 | 12°F 1910 | 45% | 6% |
| May 16 | 63°F | 38°F | 87°F 1901 | 26°F 1896 | 45% | 6% |
| May 17 | 63°F | 38°F | 87°F 1948 | 27°F 1916 | 45% | 6% |
| May 18 | 64°F | 38°F | 86°F 1937 | 23°F 1929 | 46% | 5% |
| May 19 | 64°F | 39°F | 87°F 1954 | 25°F 1903 | 46% | 5% |
| May 20 | 64°F | 39°F | 88°F 1925 | 23°F 1931 | 46% | 5% |
| May 21 | 64°F | 39°F | 89°F 1928 | 24°F 1931 | 46% | 5% |
| May 22 | 65°F | 40°F | 93°F 1928 | 24°F 1910 | 47% | 4% |
| May 23 | 65°F | 40°F | 87°F 1928 | 17°F 1930 | 47% | 4% |
| May 24 | 65°F | 40°F | 88°F 1929 | 29°F 1993 | 47% | 4% |
| May 25 | 65°F | 41°F | 92°F 1928 | 26°F 2004 | 47% | 3% |
| May 26 | 66°F | 41°F | 90°F 1936 | 26°F 1975 | 47% | 3% |
| May 27 | 66°F | 41°F | 91°F 1919 | 23°F 1910 | 47% | 3% |
| May 28 | 66°F | 42°F | 93°F 1919 | 15°F 1947 | 48% | 3% |
| May 29 | 66°F | 42°F | 92°F 1936 | 27°F 1929 | 48% | 3% |
| May 30 | 67°F | 42°F | 92°F 1936 | 30°F 1924 | 48% | 2% |
| May 31 | 67°F | 42°F | 87°F 1936 | 24°F 1982 | 48% | 2% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (MDT).
- May 1
- sunrise 6:02 AM, sunset 8:29 PM
- May 31
- sunrise 5:27 AM, sunset 9:05 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USW00024036 (Lewistown Muni AP), public domain. Records: NOAA GHCN-Daily, station USW00024036, 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 2026-09-25. Sun and moon: computed with the NOAA solar equations and Meeus.