Thornton Colorado Climate Data

Monthly Average Climate Data for Thornton Colorado

Switch Data to Fahrenheit
MonthAvg. LowAvg. HighAvg. Precip
January-7.1 °C7.7 °C12.95 mm
February-6.4 °C8.3 °C15.24 mm
March-2.2 °C13.3 °C33.53 mm
April1.3 °C16.5 °C53.59 mm
May6.4 °C21.4 °C66.8 mm
June11.6 °C28.2 °C40.89 mm
July15 °C31.7 °C48.77 mm
August13.8 °C30.4 °C38.1 mm
September9.2 °C26.1 °C35.81 mm
October2.5 °C18.7 °C28.96 mm
November-2.9 °C12.2 °C21.08 mm
December-7.2 °C7.3 °C14.22 mm
Annual2.8 °C18.5 °C409.94 mm

Climate Data for Thornton Colorado

Average First Frost DateOct. 1 - Oct. 10
Average Last Frost DateMay 21 - May 31
Average Days With Frost150-180 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 ConditionsNormal
Köppen Climate ClassificationBSk - Cold Semi-Arid Climate
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