Royal Illinois Climate Data

Monthly Average Climate Data for Royal Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January17.8 °F33.6 °F2.35 in.
February21.0 °F38.2 °F2.09 in.
March30.1 °F49.8 °F2.81 in.
April40.7 °F63.5 °F4.03 in.
May52.5 °F73.7 °F4.51 in.
June61.5 °F82.0 °F4.76 in.
July64.2 °F84.3 °F4.2 in.
August61.9 °F82.9 °F3.26 in.
September54.6 °F78.3 °F3.27 in.
October43.0 °F65.7 °F3.38 in.
November32.4 °F51.1 °F3.19 in.
December23.5 °F38.5 °F2.4 in.
Annual41.9 °F61.8 °F40.25 in.

Climate Data for Royal Illinois

Average First Frost DateOct. 11 - Oct. 20
Average Last Frost DateApr. 21 - Apr. 30
Average Days With Frost100-125 Days
Plant Hardiness Zone - 2023Zone 6a : -10°F to -5°F
Plant Hardiness Zone - 2012Zone 5b : -15°F to -10°F
Current Drought ConditionsAbnormally Dry
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation
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