Thornton Colorado Climate Data

Monthly Average Climate Data for Thornton Colorado

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January19.2 °F45.9 °F0.51 in.
February20.5 °F46.9 °F0.6 in.
March28.1 °F55.9 °F1.32 in.
April34.4 °F61.7 °F2.11 in.
May43.6 °F70.5 °F2.63 in.
June52.9 °F82.7 °F1.61 in.
July59.0 °F89.0 °F1.92 in.
August56.9 °F86.7 °F1.5 in.
September48.6 °F78.9 °F1.41 in.
October36.5 °F65.7 °F1.14 in.
November26.7 °F53.9 °F0.83 in.
December19.1 °F45.2 °F0.56 in.
Annual37.1 °F65.3 °F16.14 in.

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 : -10°F to -5°F
Plant Hardiness Zone - 2012Zone 6a : -10°F to -5°F
Current Drought ConditionsAbnormally Dry
Köppen Climate ClassificationBSk - Cold Semi-Arid Climate