Crystal Lake Illinois Climate Data

Monthly Average Climate Data for Crystal Lake Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January14.5 °F30.4 °F1.85 in.
February17.2 °F35.0 °F1.89 in.
March26.6 °F46.4 °F2.18 in.
April36.4 °F58.2 °F3.75 in.
May47.5 °F69.7 °F4.88 in.
June57.6 °F79.4 °F5.03 in.
July61.9 °F83.3 °F4.07 in.
August60.2 °F81.4 °F3.99 in.
September52.6 °F74.7 °F3.55 in.
October41.6 °F61.6 °F3.16 in.
November30.5 °F47.6 °F2.46 in.
December20.1 °F35.0 °F2.05 in.
Annual38.9 °F58.6 °F38.86 in.

Climate Data for Crystal Lake Illinois

Average First Frost DateOct. 11 - Oct. 20
Average Last Frost DateMay 11 - May 20
Average Days With Frost125-150 Days
Plant Hardiness Zone - 2023Zone 5b : -15°F to -10°F
Plant Hardiness Zone - 2012Zone 5b : -15°F to -10°F
Current Drought ConditionsModerate Drought
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation