Round Lake Illinois Climate Data

Monthly Average Climate Data for Round Lake Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January14.3 °F29.5 °F1.91 in.
February17.1 °F33.3 °F1.94 in.
March26.4 °F44.5 °F2.28 in.
April36.8 °F57.0 °F3.88 in.
May47.6 °F68.5 °F4.5 in.
June57.7 °F78.3 °F4.65 in.
July62.6 °F82.6 °F3.82 in.
August61.1 °F80.9 °F3.79 in.
September53.4 °F74.0 °F3.57 in.
October41.8 °F61.1 °F3.18 in.
November30.8 °F47.0 °F2.41 in.
December20.4 °F34.9 °F2.13 in.
Annual39.2 °F57.6 °F38.06 in.

Climate Data for Round 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