Cosmopolis, WA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Cosmopolis, a city in Grays Harbor County, Washington.
Today
84°F
Sunny then Patchy Smoke
Patchy smoke between 3pm and 5pm. Sunny, with a high near 84. North northeast wind 3 to 8 mph.
7-day forecast for Cosmopolis
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 84°F | Sunny then Patchy Smoke | 3 to 8 mph NNE | 0% |
| Tonight | 57°F | Mostly Clear then Patchy Smoke | 1 to 7 mph WNW | 0% |
| Wednesday | 86°F | Areas Of Smoke | 2 to 8 mph NNW | 0% |
| Wednesday Night | 56°F | Mostly Clear | 1 to 8 mph W | 0% |
| Thursday | 80°F | Mostly Sunny | 1 to 8 mph W | 0% |
| Thursday Night | 56°F | Partly Cloudy | 3 to 8 mph W | 0% |
| Friday | 75°F | Mostly Sunny | 3 to 10 mph W | 0% |
| Friday Night | 55°F | Mostly Clear | 6 to 10 mph WNW | 0% |
| Saturday | 73°F | Mostly Sunny | 6 to 12 mph WNW | 0% |
| Saturday Night | 55°F | Partly Cloudy | 6 to 13 mph WNW | 0% |
| Sunday | 69°F | Mostly Sunny | 6 to 10 mph WNW | 0% |
| Sunday Night | 55°F | Partly Cloudy | 5 to 10 mph WNW | 0% |
| Monday | 70°F | Mostly Sunny | 3 to 10 mph WNW | 0% |
| Monday Night | 55°F | Partly Cloudy | 3 to 10 mph WNW | 2% |
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
8b
More local growing data for Cosmopolis: nearby ZIP 98520 weather · frost dates · planting calendar · Washington frost dates
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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 Aug 4, 2026.