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Oso, WA Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Oso, a community in Snohomish County, Washington.

Today
81°F
Mostly Sunny
Mostly sunny. High near 81, with temperatures falling to around 77 in the afternoon. West southwest wind 0 to 5 mph.

7-day forecast for Oso

WhenTempForecastWindPrecip
Today 81°F Mostly Sunny 0 to 5 mph WSW 0%
Tonight 51°F Mostly Clear 0 to 5 mph NW 0%
Sunday 83°F Mostly Sunny 5 mph NW 0%
Sunday Night 51°F Partly Cloudy 0 to 5 mph NNE 0%
Monday 78°F Mostly Sunny 1 to 6 mph S 0%
Monday Night 49°F Partly Cloudy 0 to 5 mph NE 0%
Tuesday 73°F Partly Sunny 1 to 6 mph S 0%
Tuesday Night 47°F Mostly Cloudy 1 to 5 mph NE 10%
Wednesday 72°F Partly Sunny then Slight Chance Light Rain 1 to 5 mph SW 16%
Wednesday Night 48°F Slight Chance Light Rain then Mostly Cloudy 3 mph N 16%
Thursday 70°F Mostly Cloudy then Slight Chance Light Rain 1 to 5 mph ENE 19%
Thursday Night 47°F Chance Light Rain 1 to 5 mph N 27%
Friday 69°F Chance Light Rain 3 mph WNW 27%
Friday Night 45°F Slight Chance Light Rain 5 mph NNE 16%

Forecast source: National Weather Service (api.weather.gov) for Oso (48.284, -121.916). Updated through the day.

Growing snapshot for Oso

Last spring frost
Apr 22
First fall frost
Oct 19
Growing season
181 days
Hardiness zone
8b

More local growing data for Oso: nearby ZIP 98223 weather · frost dates · planting calendar · Washington frost dates

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Climate data from the nearest NOAA station, Arlington, Wa (8.1 mi from Oso). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.