Grand Coulee Washington Climate Data

Monthly Average Climate Data for Grand Coulee Washington

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January24.4 °F34.6 °F1.22 in.
February26.2 °F40.9 °F0.87 in.
March31.5 °F51.8 °F1.02 in.
April37.0 °F61.7 °F0.92 in.
May44.6 °F71.6 °F1.1 in.
June50.9 °F78.5 °F1.04 in.
July57.6 °F88.7 °F0.49 in.
August57.3 °F88.3 °F0.32 in.
September49.4 °F78.4 °F0.37 in.
October39.6 °F62.3 °F0.83 in.
November31.4 °F45.5 °F1.14 in.
December25.2 °F35.2 °F1.44 in.
Annual39.6 °F61.5 °F10.76 in.

Climate Data for Grand Coulee Washington

Average First Frost DateOct. 11 - Oct. 20
Average Last Frost DateMay 1 - May 10
Average Days With Frost100-125 Days
Plant Hardiness Zone - 2023Zone 7a : 0°F to 5°F
Plant Hardiness Zone - 2012Zone 7a : 0°F to 5°F
Current Drought ConditionsNormal
Köppen Climate ClassificationDsb - Humid Continental Climate - Dry Cool Summer