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Crystal Lake, IL weather and climate

McHenry County, IL · population 40,436 · about 902 ft elevation

Everything below is a 30 year average for 1991-2020, computed from daily climate history at Crystal Lake's own coordinates.

The year at a glance

Sunny days
182
clear or partly cloudy, per year
Precipitation
36 in
per year
Wet days
125
rain or snow per year
Snowfall
36 in
per year
Hot days
18
above 90 °F
Freezing nights
137
at or below 32 °F
Humidity
71%
average relative
Average temperature
49 °F
year round

Monthly temperatures

Average daily high and low for each month, in °F.

Daily highDaily low
255075JanMarMayJulSepNovDaily high, Jan: 31 °FDaily high, Feb: 35 °FDaily high, Mar: 46 °FDaily high, Apr: 59 °FDaily high, May: 71 °FDaily high, Jun: 80 °FDaily high, Jul: 84 °FDaily high, Aug: 82 °FDaily high, Sep: 74 °FDaily high, Oct: 62 °FDaily high, Nov: 47 °FDaily high, Dec: 35 °FDaily low, Jan: 14 °FDaily low, Feb: 16 °FDaily low, Mar: 26 °FDaily low, Apr: 37 °FDaily low, May: 48 °FDaily low, Jun: 58 °FDaily low, Jul: 62 °FDaily low, Aug: 61 °FDaily low, Sep: 52 °FDaily low, Oct: 42 °FDaily low, Nov: 30 °FDaily low, Dec: 20 °F
View monthly temperatures as a table
Monthly temperatures (°F)
CityJanFebMarAprMayJunJulAugSepOctNovDec
Daily high313546597180848274624735
Daily low141626374858626152423020

Monthly precipitation

Total rain plus melted snow for each month, in inches.

0.02.04.0JanMarMayJulSepNovCrystal Lake, Jan: 2.0 inCrystal Lake, Feb: 1.9 inCrystal Lake, Mar: 2.5 inCrystal Lake, Apr: 4.3 inCrystal Lake, May: 4.3 inCrystal Lake, Jun: 3.8 inCrystal Lake, Jul: 3.4 inCrystal Lake, Aug: 3.6 inCrystal Lake, Sep: 3.0 inCrystal Lake, Oct: 3.0 inCrystal Lake, Nov: 2.4 inCrystal Lake, Dec: 2.1 in
View monthly precipitation as a table
Monthly precipitation (inches)
CityJanFebMarAprMayJunJulAugSepOctNovDec
Crystal Lake2.01.92.54.34.33.83.43.63.03.02.42.1

Monthly sunny days

Days each month with clear or partly cloudy skies.

01020JanMarMayJulSepNovCrystal Lake, Jan: 11 daysCrystal Lake, Feb: 12 daysCrystal Lake, Mar: 14 daysCrystal Lake, Apr: 14 daysCrystal Lake, May: 15 daysCrystal Lake, Jun: 16 daysCrystal Lake, Jul: 20 daysCrystal Lake, Aug: 20 daysCrystal Lake, Sep: 20 daysCrystal Lake, Oct: 16 daysCrystal Lake, Nov: 14 daysCrystal Lake, Dec: 12 days
View monthly sunny days as a table
Monthly sunny days (days)
CityJanFebMarAprMayJunJulAugSepOctNovDec
Crystal Lake111214141516202020161412

Compare Crystal Lake with another city

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About this data

Figures are 30 year averages for 1991-2020. Wet days count days with measurable precipitation, calibrated against the wet day counts in NOAA's published climate normals. Sunny days count clear plus partly cloudy days, defined as average cloud cover of 63 percent or less and calibrated against NOAA's published sky cover tables. Snowfall figures are model estimates anchored to NOAA station measurements near each city.

Weather data by Open-Meteo.com (CC BY 4.0). Contains modified Copernicus Climate Change Service information (ERA5, ERA5-Land).