Roundup Weather in May
Average highs run from 64°F on May 1 to 73°F on May 31, and lows from 34°F to 45°F. Normal precipitation for the month is 2.55 in over about 10 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
- 69°F
- Average low
- 39°F
- Precipitation
- 2.55 in
- Snowfall
- 0.1 in
- Record high
- 97°FMay 22, 1980
- Record low
- 6°FMay 2, 1954
- Chance of a freeze
- 96%
- Days of 90°F or more
- 0.8
- Daylight
- 14 h 24 min to 15 h 33 min
- Cloud cover
- 67%
- Humidity
- 58%
- Dew point
- 37°F
- Wind
- 9.8 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 | 64°F | 34°F | 86°F 1981 | 14°F 2013 | 28% | 1% |
| May 2 | 65°F | 34°F | 89°F 1985 | 6°F 1954 | 29% | 1% |
| May 3 | 65°F | 34°F | 90°F 1985 | 8°F 1954 | 29% | 1% |
| May 4 | 65°F | 35°F | 85°F 1966 | 9°F 1954 | 29% | 1% |
| May 5 | 66°F | 35°F | 87°F 1934 | 20°F 2006 | 29% | 1% |
| May 6 | 66°F | 36°F | 88°F 1966 | 22°F 1999 | 30% | 1% |
| May 7 | 66°F | 36°F | 87°F 1987 | 16°F 1945 | 30% | 1% |
| May 8 | 67°F | 36°F | 88°F 1987 | 14°F 1945 | 30% | 1% |
| May 9 | 67°F | 37°F | 88°F 1977 | 18°F 2002 | 31% | 1% |
| May 10 | 67°F | 37°F | 90°F 1977 | 13°F 1946 | 31% | 1% |
| May 11 | 68°F | 37°F | 90°F 1960 | 21°F 1946 | 31% | 1% |
| May 12 | 68°F | 38°F | 90°F 1941 | 16°F 1943 | 32% | 0% |
| May 13 | 68°F | 38°F | 89°F 2001 | 21°F 1953 | 32% | 0% |
| May 14 | 69°F | 39°F | 93°F 1936 | 22°F 1953 | 32% | 0% |
| May 15 | 69°F | 39°F | 90°F 1987 | 27°F 1943 | 33% | 0% |
| May 16 | 69°F | 39°F | 92°F 1934 | 27°F 1937 | 33% | 0% |
| May 17 | 70°F | 40°F | 89°F 1988 | 27°F 1974 | 33% | 0% |
| May 18 | 70°F | 40°F | 87°F 1992 | 26°F 1968 | 34% | 0% |
| May 19 | 70°F | 41°F | 93°F 1954 | 26°F 1997 | 34% | 0% |
| May 20 | 70°F | 41°F | 89°F 1958 | 27°F 1968 | 34% | 0% |
| May 21 | 71°F | 41°F | 93°F 1980 | 23°F 1963 | 35% | 0% |
| May 22 | 71°F | 42°F | 97°F 1980 | 26°F 2022 | 35% | 0% |
| May 23 | 71°F | 42°F | 95°F 1980 | 28°F 1947 | 36% | 0% |
| May 24 | 72°F | 42°F | 92°F 1941 | 28°F 1954 | 36% | 0% |
| May 25 | 72°F | 43°F | 90°F 1934 | 20°F 2012 | 36% | 0% |
| May 26 | 72°F | 43°F | 94°F 1934 | 22°F 2012 | 36% | 0% |
| May 27 | 72°F | 43°F | 93°F 1934 | 27°F 2012 | 37% | 0% |
| May 28 | 73°F | 44°F | 95°F 1934 | 16°F 1947 | 37% | 0% |
| May 29 | 73°F | 44°F | 96°F 1936 | 30°F 1947 | 37% | 0% |
| May 30 | 73°F | 44°F | 95°F 1936 | 32°F 1954 | 37% | 0% |
| May 31 | 73°F | 45°F | 92°F 1936 | 27°F 1982 | 37% | 0% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (MDT).
- May 1
- sunrise 6:00 AM, sunset 8:24 PM
- May 31
- sunrise 5:26 AM, sunset 8:59 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00247214 (Roundup), public domain. Records: NOAA GHCN-Daily, station USC00243727, 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.