McHenry climate — normals and trends
McHenry (United States) has a hot-summer humid continental climate (Dfa) under the Köppen-Geiger classification. Its mean annual temperature is 9.2 °C and it receives 874 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is July (22.9 °C on average) and the coldest is January (-5.8 °C). Rainfall peaks in April.
McHenry averages 123 frost days, 21 hot days (≥ 30 °C) and 115 rainy days per year.
McHenry has warmed by +2.1 °C between 1940 and 2025, or +0.24 °C per decade. This trend is statistically significant.
The number of frost days there went from about 137 to 109 per year over the period.
The hottest day of the period reached 38.6 °C (on 25 June 1988) and the coldest -33.2 °C (on 3 February 1996).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
McHenryIllinois
- coords
- 42.33°, -88.27°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
9.2°C
Average daily high
13.7°C
Average daily low
4.9°C
Annual rainfall
874mm
Sunshine / day
8.7h
Mean relative humidity
71%
Average peak wind
18.9km/h
Seasonal range
28.7°C
Frost days (< 0 °C)
123 d/yr
Hot days (≥ 30 °C)
21 d/yr
Rainy days (≥ 1 mm)
115 d/yr
Annual snowfall
80.8 cm
Average feels-like high
11.7 °C
Average feels-like low
1.9 °C
Average peak gust
39.8 km/h
Tropical nights (≥ 20 °C)
24 d/yr
Solar radiation
14.6 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.1 °C
since 1940
+0.2 °C per decade · r² = 0.38 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
38.6 °C
25 June 1988
Coldest day
-33.2 °C
3 February 1996
Wettest day
95 mm
13 September 2008
Windiest day
51.3 km/h
6 April 1997
Strongest gust
117.7 km/h
10 November 1998
Hottest feels-like
44.0 °C
6 July 2012
Coldest feels-like
-38.7 °C
3 February 1996
Snowiest day
25.4 cm
1 January 1948
Sunniest day
14.6 h
16 June 2021
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | -1.7 °C | +0.3 °C | 25 mm | -23 mm |
| Feb | 0.2 °C | 0.0 °C | 27 mm | -15 mm |
| Mar | 11.8 °C | +5.4 °C | 92 mm | +23 mm |
| Apr | 14.7 °C | +1.1 °C | 76 mm | -22 mm |
| May | 18.4 °C | -1.4 °C | 92 mm | -3 mm |
| Jun | 27.3 °C | +1.9 °C | 105 mm | +12 mm |
| Jul | 28.5 °C | +0.9 °C | 123 mm | +36 mm |
| Aug | 26.1 °C | -0.5 °C | 79 mm | -4 mm |
| Sep | 24.5 °C | +1.8 °C | 60 mm | -14 mm |
| Oct | 17.8 °C | +1.7 °C | 51 mm | -17 mm |
| Nov | 8.8 °C | +1.1 °C | 52 mm | -9 mm |
| Dec | 0.3 °C | -0.4 °C | 56 mm | +2 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of McHenry?
McHenry has a hot-summer humid continental climate (Köppen Dfa). Over 1940-2025, the average annual temperature is 9.2 °C and it receives 874 mm of precipitation per year.
What is the hottest day ever recorded in McHenry?
The hottest day measured in McHenry between 1940 and 2025 was 25 June 1988, reaching 38.6 °C.
What is the coldest day in McHenry?
The coldest day measured in McHenry between 1940 and 2025 was 3 February 1996, at -33.2 °C.
Does it snow in McHenry?
Yes. McHenry gets on average 80.8 cm of snow per year and has around 123 frost days.
Has the climate of McHenry warmed?
Yes: McHenry warmed by +2.1 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in McHenry?
The wettest day measured in McHenry between 1940 and 2025 was 13 September 2008, with 95 mm of rain in 24 hours.
What was the windiest day in McHenry?
The windiest day measured in McHenry between 1940 and 2025 was 6 April 1997, with winds reaching 51.3 km/h.
What is the warmest month in McHenry?
The warmest month in McHenry is July (22.9 °C on average); the coldest is January (-5.8 °C).
How much does it rain in McHenry?
McHenry receives on average 874 mm of precipitation per year, spread over about 115 rainy days.
Is it sunny in McHenry?
McHenry gets on average 8.7 hours of sunshine per day, roughly 3,175 hours per year over 1940-2025.
What is the biggest single-day snowfall in McHenry?
The heaviest 24-hour snowfall measured in McHenry between 1940 and 2025 was 1 January 1948, with 25.4 cm.
Are there tropical nights in McHenry?
Yes: McHenry has on average 24 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in McHenry?
In McHenry, between 1940 and 2025, the highest apparent temperature reached 44.0 °C on 6 July 2012, and the lowest was -38.7 °C on 3 February 1996.
Compare McHenry with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around McHenry