Frost Dates for Grand Coulee, WA

Based on data from Coulee Dam 1 Sw weather station, 1 miles away

Elevation: 1483 ft

Frost Dates

Last Spring Frost (50%) A 50% chance that the last spring frost has already passed by this date. Most gardeners use this as their primary planting guide. April 22
First Fall Frost (50%) A 50% chance that the first fall frost has occurred by this date. Plan to harvest or protect tender plants before this date. October 21

30% Probability

Only a 30% chance of frost remaining by this date. Use these dates for a safer planting window, especially for tender plants sensitive to cold.
Last Spring Frost April 29
First Fall Frost October 16

Hard Freeze (28°F)

Last Spring Hard Freeze April 1
First Fall Hard Freeze November 1
47.94°N, 119.00°W © OpenStreetMap

Growing Season

182 Days April 22 to October 21

USDA Hardiness Zone

Hardiness zones indicate which perennial plants can survive winter in your area. For annual vegetables, frost dates and growing season length matter more than hardiness zone.
Zone 7a

Avg. annual minimum: 0 to 5°F

Learn more

Köppen Climate

The Köppen climate classification system categorizes climates based on temperature and precipitation patterns.
BSk Cold Semi-Arid (Steppe)

Cool to cold with low rainfall and wide temperature swings. Common in the western Great Plains and central Asia. Short growing seasons benefit from season extension techniques.

Köppen climate map

Temperature

Avg High Avg Temp Avg Low Light Frost (32°F) Hard Frost (28°F)
Temperature table
Average monthly temperatures (°F)
Month Avg High Avg Temp Avg Low
January33°28°23°
February40°32°25°
March51°41°32°
April61°49°38°
May71°58°46°
June78°65°52°
July88°74°59°
August87°73°58°
September77°64°51°
October60°50°40°
November43°37°31°
December33°29°24°

Precipitation

Precipitation table
Average monthly precipitation (inches)
MonthPrecipitation
January1.7
February1.4
March1.5
April1.2
May1.7
June2.4
July1.3
August0.0
September1.5
October1.7
November1.5
December1.7

Sunrise / Sunset

Daylight Pacific Time (PT) Longest: 15h 50m · Shortest: 8h 10m
Sunrise and sunset table
Sunrise, sunset, and daylight on the 15th of each month (Pacific Time (PT))
Month Sunrise Sunset Daylight
January7:48 AM4:23 PM8h 35m
February7:11 AM5:10 PM9h 59m
March7:18 AM6:53 PM11h 35m
April6:14 AM7:39 PM13h 25m
May5:24 AM8:21 PM14h 57m
June5:02 AM8:50 PM15h 48m
July5:18 AM8:45 PM15h 27m
August5:57 AM8:03 PM14h 06m
September6:41 AM7:00 PM12h 20m
October7:24 AM5:58 PM10h 34m
November7:12 AM4:11 PM8h 59m
December7:46 AM3:58 PM8h 11m

Nearby Stations

Wilbur, WAJune 1 - September 22 Hartline, WAMay 2 - October 12 Chief Joseph Dam, WA April 26 - October 11 Omak AP, WAApril 30 - October 7 Davenport, WA June 6 - September 11 Odessa, WAMay 14 - September 26

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