Cosmopolis, WA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Cosmopolis, a city in Grays Harbor County, Washington.
Tonight
38°F
Partly Cloudy
Partly cloudy, with a low around 38. East wind 0 to 3 mph.
7-day forecast for Cosmopolis
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 38°F | Partly Cloudy | 0 to 3 mph E | 4% |
| Wednesday | 57°F | Mostly Cloudy then Light Rain | 5 mph ESE | 85% |
| Wednesday Night | 46°F | Light Rain | 3 to 7 mph SSW | 100% |
| Thursday | 57°F | Slight Chance Light Rain | 3 to 7 mph SSW | 16% |
| Thursday Night | 48°F | Light Rain | 3 to 7 mph S | 89% |
| Friday | 56°F | Light Rain | 3 to 9 mph S | 89% |
| Friday Night | 48°F | Chance Light Rain | 6 mph SE | 46% |
| Saturday | 60°F | Light Rain Likely | 8 mph SSE | 59% |
| Saturday Night | 50°F | Showers And Thunderstorms | 8 to 17 mph S | 89% |
| Sunday | 57°F | Light Rain Likely | 3 to 12 mph SW | 63% |
| Sunday Night | 44°F | Chance Light Rain | 5 mph SE | 35% |
| Monday | 55°F | Light Rain Likely | 7 mph ESE | 60% |
| Monday Night | 49°F | Light Rain | 6 to 13 mph SSE | 79% |
| Tuesday | 57°F | Light Rain | 8 to 12 mph SSE | 79% |
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
Nearby towns & communities
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Markham
McCleary
Moclips
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Neilton
Oakville
Ocean City
Ocean Shores
Ocosta
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Qui-nai-elt Village
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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 Nov 4, 2026.