SeaTac Washington Climate Data

Monthly Average Climate Data for SeaTac Washington

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January36.0 °F46.9 °F6.18 in.
February35.9 °F49.4 °F4.37 in.
March38.3 °F53.3 °F4.9 in.
April41.6 °F58.7 °F3.69 in.
May46.9 °F65.6 °F2.14 in.
June51.3 °F69.9 °F1.65 in.
July54.9 °F76.5 °F0.76 in.
August55.1 °F77.0 °F0.89 in.
September51.4 °F71.1 °F1.56 in.
October45.1 °F60.2 °F4.62 in.
November39.2 °F51.2 °F6.62 in.
December35.6 °F46.0 °F6.44 in.
Annual44.3 °F60.5 °F43.82 in.

Climate Data for SeaTac Washington

Average First Frost DateNov. 11 - Nov. 20
Average Last Frost DateMar. 21 - Mar. 31
Average Days With Frost20-30 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