Sullivan Illinois Climate Data

Monthly Average Climate Data for Sullivan Illinois

Switch Data to Fahrenheit
MonthAvg. LowAvg. HighAvg. Precip
January-7.1 °C1.8 °C60.45 mm
February-5.3 °C4.5 °C55.37 mm
March-0.3 °C10.7 °C73.91 mm
April5.6 °C17.8 °C114.05 mm
May12 °C23.6 °C121.67 mm
June16.9 °C28.4 °C119.38 mm
July18.6 °C30 °C102.62 mm
August17.2 °C29.3 °C72.9 mm
September12.9 °C26.6 °C76.2 mm
October6.7 °C19.6 °C85.34 mm
November0.7 °C11.2 °C84.07 mm
December-3.8 °C4.5 °C64.26 mm
Annual6.2 °C17.3 °C1030.22 mm

Climate Data for Sullivan 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 : -23.3°C to -20.6°C
Plant Hardiness Zone - 2012Zone 6a : -23.3°C to -20.6°C
Current Drought ConditionsModerate Drought
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation
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