Grand Coulee Washington Climate Data

Monthly Average Climate Data for Grand Coulee Washington

Switch Data to Fahrenheit
MonthAvg. LowAvg. HighAvg. Precip
January-4.2 °C1.4 °C30.99 mm
February-3.2 °C4.9 °C22.1 mm
March-0.3 °C11 °C25.91 mm
April2.8 °C16.5 °C23.37 mm
May7 °C22 °C27.94 mm
June10.5 °C25.8 °C26.42 mm
July14.2 °C31.5 °C12.45 mm
August14.1 °C31.3 °C8.13 mm
September9.7 °C25.8 °C9.4 mm
October4.2 °C16.8 °C21.08 mm
November-0.3 °C7.5 °C28.96 mm
December-3.8 °C1.8 °C36.58 mm
Annual4.2 °C16.4 °C273.33 mm

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 : -17.8°C to -15°C
Plant Hardiness Zone - 2012Zone 7a : -17.8°C to -15°C
Current Drought ConditionsNormal
Köppen Climate ClassificationDsb - Humid Continental Climate - Dry Cool Summer