Harman US

SeaTac, WA Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for SeaTac, a city in King County, Washington.

Tonight
53°F
Mostly Clear
Mostly clear, with a low around 53. North wind around 3 mph.

7-day forecast for SeaTac

WhenTempForecastWindPrecip
Tonight 53°F Mostly Clear 3 mph N 0%
Sunday 73°F Mostly Sunny 1 to 6 mph N 0%
Sunday Night 52°F Partly Cloudy 1 to 6 mph N 0%
Monday 71°F Partly Sunny 1 to 5 mph N 0%
Monday Night 54°F Partly Cloudy 5 mph NNE 1%
Tuesday 69°F Mostly Cloudy 5 mph WNW 1%
Tuesday Night 53°F Mostly Cloudy 3 mph SSW 6%
Wednesday 68°F Partly Sunny 5 mph SSW 8%
Wednesday Night 52°F Mostly Cloudy 5 mph N 11%
Thursday 64°F Partly Sunny then Slight Chance Light Rain 2 to 7 mph NNE 18%
Thursday Night 51°F Slight Chance Light Rain 2 to 7 mph N 19%
Friday 63°F Slight Chance Light Rain 2 to 8 mph N 19%
Friday Night 49°F Mostly Cloudy 7 mph NE 14%
Saturday 65°F Partly Sunny 5 to 8 mph N 7%

Forecast source: National Weather Service (api.weather.gov) for SeaTac (47.443, -122.298). Updated through the day.

Growing snapshot for SeaTac

Last spring frost
Mar 2
First fall frost
Nov 23
Growing season
266 days
Hardiness zone
9a

More local growing data for SeaTac: nearby ZIP 98158 weather · frost dates · planting calendar · Washington frost dates

Nearby towns & communities

All Washington locations ›

Climate data from the nearest NOAA station, Seattle Tacoma Intl Ap, Wa (0.5 mi from SeaTac). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 20, 2026.