Johnston City Illinois Climate Data

Monthly Average Climate Data for Johnston City Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January23.9 °F40.8 °F3.55 in.
February27.0 °F45.8 °F3.03 in.
March35.4 °F55.9 °F4.43 in.
April45.5 °F67.3 °F5.42 in.
May55.9 °F76.2 °F5.1 in.
June64.5 °F84.6 °F4.47 in.
July67.9 °F87.6 °F4.0 in.
August65.5 °F86.9 °F3.08 in.
September57.4 °F81.1 °F3.15 in.
October45.7 °F69.7 °F3.5 in.
November35.8 °F56.2 °F4.32 in.
December28.0 °F45.1 °F3.54 in.
Annual46 °F66.4 °F47.59 in.

Climate Data for Johnston City Illinois

Average First Frost DateOct. 11 - Oct. 20
Average Last Frost DateApr. 11 - Apr. 20
Average Days With Frost75-100 Days
Plant Hardiness Zone - 2023Zone 7a : 0°F to 5°F
Plant Hardiness Zone - 2012Zone 6b : -5°F to 0°F
Current Drought ConditionsNormal
Köppen Climate ClassificationCfa - Humid Subtropical Climate
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