Cosmopolis, WA Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Cosmopolis, a city in Grays Harbor County, Washington.

Overnight

38°F

Partly Cloudy

Partly cloudy, with a low around 38. East southeast wind around 3 mph.

7-day forecast for Cosmopolis

When	Temp	Forecast	Wind	Precip
Overnight	38°F	Partly Cloudy	3 mph ESE	1%
Wednesday	57°F	Mostly Cloudy then Light Rain	2 to 8 mph SE	100%
Wednesday Night	46°F	Light Rain	5 to 13 mph SSW	86%
Thursday	57°F	Partly Sunny	5 to 8 mph SSW	12%
Thursday Night	46°F	Light Rain	8 mph SSE	92%
Friday	55°F	Light Rain	6 to 15 mph SSE	92%
Friday Night	49°F	Light Rain	6 mph SSE	77%
Saturday	61°F	Light Rain	7 mph SE	79%
Saturday Night	50°F	Light Rain	7 to 17 mph SSW	89%
Sunday	57°F	Light Rain Likely	2 to 9 mph SW	62%
Sunday Night	44°F	Slight Chance Light Rain	0 to 5 mph SE	15%
Monday	56°F	Chance Light Rain	6 mph ESE	51%
Monday Night	48°F	Light Rain Likely	6 to 10 mph SSE	67%
Tuesday	57°F	Light Rain Likely	7 to 12 mph SSE	67%

Forecast source: National Weather Service (api.weather.gov) for Cosmopolis (46.954, -123.773). Updated through the day.

Growing snapshot for Cosmopolis

Last spring frost

Mar 29

First fall frost

Nov 15

Growing season

234 days

Hardiness zone

More local growing data for Cosmopolis: nearby ZIP 98520 weather · frost dates · planting calendar · Washington frost dates

Nearby towns & communities

Aberdeen Aberdeen Gardens Amanda Park Brady Central Park Cohassett Beach Copalis Beach Elma Grayland Hogans Corner Hoquiam Humptulips Malone Markham McCleary Moclips Montesano Neilton Oakville Ocean City Ocean Shores Ocosta Oyehut Pacific Beach Porter Qui-nai-elt Village Santiago Satsop Taholah Westport

All Washington locations ›

Climate data from the nearest NOAA station, Aberdeen, Wa (1.6 mi from Cosmopolis). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.