McHenry, IL Weather & Climate Normals
What a normal year in McHenry actually looks like
On the 30-year record NOAA keeps for McHenry, IL, the comfort score comes out to 44/100, strongly seasonal: Comfortable weather is limited to a shorter window; summers, winters, or precipitation swing wide. Only 5 months a year land in the 55–75°F range this site treats as mild.
How much McHenry's weather actually swings
Average temperatures in McHenry run from 22°F in Jan up to 73°F in Jul, a 51.1°F seasonal swing, one of the widest gaps in this dataset.
McHenry, month by month
| Month | Avg high | Avg low | Precip | Snow |
|---|---|---|---|---|
| Jan | 31°F | 13°F | 1.65in | 11in |
| Feb | 35°F | 16°F | 1.56in | 8.9in |
| Mar | 46°F | 26°F | 2.21in | 3.9in |
| Apr | 59°F | 37°F | 3.63in | 1in |
| May | 70°F | 47°F | 4.47in | 0in |
| Jun | 80°F | 57°F | 4.81in | 0in |
| Jul | 84°F | 62°F | 3.8in | 0in |
| Aug | 82°F | 60°F | 3.7in | 0in |
| Sep | 76°F | 51°F | 3.61in | 0in |
| Oct | 63°F | 40°F | 3.21in | 0.1in |
| Nov | 48°F | 29°F | 2.38in | 1.4in |
| Dec | 36°F | 19°F | 1.94in | 8.2in |
If you're timing a visit, May, Jun, Jul, Aug, and Sep are McHenry's mildest stretch; if you're moving there, you should plan around Jan's cold instead.
How wet McHenry actually gets
Over a typical year, McHenry sees about 36.97in of precipitation a year across roughly 119 days with measurable rain or snow, with 34.5in of snow a year.
McHenry against the rest of the country
Out of 4876 cities scored here, McHenry comes in at 3728; within IL alone it ranks 179 of 330. Population is about 28,825.
Checking the actual forecast
These figures come from Mc Henry -Wg Stratton L&D, IL US, the NOAA station 2.7 miles from McHenry, averaged over 30 years, not tomorrow's forecast.
More on how this is worked out
Why some cities show no snow or rain figure · What a 30-year climate normal actually is