McHenry County Weather in May
Average highs run from 63°F on May 1 to 74°F on May 31, and lows from 34°F to 46°F. Normal precipitation for the month is 2.34 in over about 5 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
- 40°F
- Precipitation
- 2.34 in
- Snowfall
- 0.8 in
- Record high
- 99°FMay 11, 2025
- Record low
- 17°FMay 2, 2002
- Chance of a freeze
- 97%
- Days of 90°F or more
- 0.5
- Daylight
- 14 h 33 min to 15 h 47 min
- Cloud cover
- 63%
- Humidity
- 60%
- Dew point
- 39°F
- Wind
- 11.9 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 | 63°F | 34°F | 83°F 1955 | 20°F 1958 | 15% | 1% |
| May 2 | 63°F | 34°F | 89°F 1955 | 17°F 2002 | 15% | 1% |
| May 3 | 63°F | 35°F | 90°F 1952 | 19°F 1967 | 15% | 1% |
| May 4 | 64°F | 35°F | 88°F 2016 | 23°F 1967 | 15% | 1% |
| May 5 | 64°F | 35°F | 95°F 2016 | 25°F 1968 | 16% | 1% |
| May 6 | 65°F | 36°F | 88°F 1992 | 21°F 2026 | 16% | 1% |
| May 7 | 65°F | 36°F | 84°F 1992 | 23°F 2002 | 16% | 1% |
| May 8 | 66°F | 37°F | 87°F 1985 | 25°F 2010 | 17% | 1% |
| May 9 | 66°F | 37°F | 86°F 2007 | 22°F 1981 | 17% | 1% |
| May 10 | 66°F | 37°F | 94°F 2025 | 25°F 2021 | 17% | 1% |
| May 11 | 67°F | 38°F | 99°F 2025 | 21°F 2005 | 17% | 1% |
| May 12 | 67°F | 38°F | 95°F 2025 | 26°F 1953 | 18% | 1% |
| May 13 | 68°F | 39°F | 90°F 2001 | 21°F 2004 | 18% | 1% |
| May 14 | 68°F | 39°F | 90°F 2001 | 24°F 2004 | 18% | 1% |
| May 15 | 68°F | 39°F | 93°F 1987 | 27°F 1983 | 18% | 1% |
| May 16 | 69°F | 40°F | 88°F 1979 | 23°F 2002 | 19% | 1% |
| May 17 | 69°F | 40°F | 95°F 1994 | 23°F 2002 | 19% | 1% |
| May 18 | 70°F | 41°F | 89°F 2006 | 27°F 2002 | 19% | 1% |
| May 19 | 70°F | 41°F | 95°F 1992 | 27°F 2002 | 19% | 1% |
| May 20 | 70°F | 41°F | 92°F 1964 | 28°F 1963 | 20% | 0% |
| May 21 | 71°F | 42°F | 96°F 1980 | 26°F 1963 | 20% | 0% |
| May 22 | 71°F | 42°F | 99°F 1980 | 28°F 1963 | 21% | 0% |
| May 23 | 71°F | 43°F | 91°F 2006 | 29°F 1949 | 21% | 0% |
| May 24 | 72°F | 43°F | 91°F 1977 | 33°F 1949 | 21% | 0% |
| May 25 | 72°F | 43°F | 92°F 2018 | 31°F 1992 | 22% | 0% |
| May 26 | 72°F | 44°F | 94°F 1969 | 32°F 1984 | 22% | 0% |
| May 27 | 72°F | 44°F | 96°F 1969 | 28°F 2008 | 22% | 0% |
| May 28 | 73°F | 45°F | 95°F 2026 | 29°F 1965 | 23% | 0% |
| May 29 | 73°F | 45°F | 97°F 1988 | 33°F 1998 | 23% | 0% |
| May 30 | 73°F | 45°F | 91°F 1984 | 32°F 2015 | 23% | 0% |
| May 31 | 74°F | 46°F | 94°F 1986 | 34°F 1952 | 24% | 0% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (CDT).
- May 1
- sunrise 6:24 AM, sunset 8:57 PM
- May 31
- sunrise 5:47 AM, sunset 9:34 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00328792 (Towner 2 Ne), public domain. Records: NOAA GHCN-Daily, station USW00024013, 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.