Grand Coulee, WA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Grand Coulee, a city in Grant County, Washington.
Overnight
38°F
Partly Cloudy
Partly cloudy, with a low around 38. Northwest wind around 1 mph.
7-day forecast for Grand Coulee
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 38°F | Partly Cloudy | 1 mph NW | 1% |
| Wednesday | 56°F | Sunny | 0 to 6 mph S | 2% |
| Wednesday Night | 39°F | Chance Rain Showers | 5 mph SE | 40% |
| Thursday | 55°F | Mostly Sunny | 3 mph SE | 11% |
| Thursday Night | 38°F | Partly Cloudy | 6 mph SE | 8% |
| Friday | 55°F | Mostly Cloudy | 5 to 8 mph SE | 8% |
| Friday Night | 41°F | Mostly Cloudy | 5 mph E | 9% |
| Saturday | 60°F | Partly Sunny | 6 mph E | 6% |
| Saturday Night | 43°F | Mostly Cloudy then Slight Chance Rain Showers | 5 to 8 mph SE | 15% |
| Sunday | 60°F | Slight Chance Rain Showers then Partly Sunny | 8 to 16 mph SW | 15% |
| Sunday Night | 40°F | Mostly Cloudy | 3 to 8 mph S | 1% |
| Monday | 57°F | Partly Sunny then Slight Chance Rain Showers | 5 mph NE | 15% |
| Monday Night | 41°F | Chance Rain Showers | 2 to 6 mph E | 32% |
| Tuesday | 59°F | Chance Rain Showers | 3 to 8 mph SE | 32% |
Forecast source: National Weather Service (api.weather.gov) for Grand Coulee (47.939, -119.002). Updated through the day.
Growing snapshot for Grand Coulee
Last spring frost
Apr 22
First fall frost
Oct 21
Growing season
180 days
Hardiness zone
7a
More local growing data for Grand Coulee: nearby ZIP 99123 weather · frost dates · planting calendar · Washington frost dates
Nearby towns & communities
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Krupp
Lakeview
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Moses Lake
Moses Lake North
Quincy
Royal City
Schwana
Soap Lake
Sunland Estates
Vantage
Warden
Wheeler
Wilson Creek
Climate data from the nearest NOAA station, Coulee Dam 1 Sw, Wa (5.3 mi from Grand Coulee). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.