Issaquah Washington Climate Data

Monthly Average Climate Data for Issaquah Washington

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January36.1 °F47.3 °F6.17 in.
February36.2 °F50.0 °F4.46 in.
March38.7 °F54.0 °F5.03 in.
April42.2 °F58.7 °F3.94 in.
May47.6 °F65.4 °F2.44 in.
June52.0 °F69.5 °F2.15 in.
July55.5 °F75.7 °F0.87 in.
August55.7 °F76.2 °F1.13 in.
September51.7 °F70.7 °F1.92 in.
October45.4 °F60.1 °F4.76 in.
November39.7 °F51.9 °F6.77 in.
December35.8 °F46.4 °F6.32 in.
Annual44.7 °F60.5 °F45.96 in.

Climate Data for Issaquah Washington

Average First Frost DateOct. 21 - Oct. 31
Average Last Frost DateApr. 21 - Apr. 30
Average Days With Frost50-75 Days
Plant Hardiness Zone - 2023Zone 9a : 20°F to 25°F
Plant Hardiness Zone - 2012Zone 8b : 15°F to 20°F
Current Drought ConditionsAbnormally Dry
Köppen Climate ClassificationCsb - Warm-Summer Mediterranean Climate