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When to plant in Grand Coulee, WA

Planting dates worked out from Grand Coulee's own frost records, not a generic zone chart.

Safe to plant out
May 8
1 year in 10 has a later frost
Average last frost
Apr 23
about a 50% chance of a later one
Average first fall frost
Oct 20
1 year in 10 by Oct 10
Frost-free days
178
median, 1991–2020

Station used: Coulee Dam 1 Sw · 1.5 km away · station 524 m, town 452 m. How we match towns to stations

This season

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Planting dates for common crops

CropStart indoorsPlant out or sowHarvest from
Tomato Mar 13 – Mar 27 May 8 – May 22 Jul 2
Sweet pepper Feb 27 – Mar 13 May 8 – May 22 Jul 7
Lettuce (leaf) Feb 19 – Feb 26 Mar 26 – Apr 9 May 5
Peas — Mar 22 – Apr 19 May 16
Bush beans — May 1 – May 22 Jun 20
Carrot — Apr 5 – May 17 Jun 4
Beet — Apr 5 – May 17 May 25
Potato — Apr 5 – Apr 26 Jun 14
Kale Feb 15 – Mar 1 Mar 29 – Apr 12 May 11
Broccoli Feb 12 – Feb 26 Mar 26 – Apr 16 May 25
Cucumber Apr 10 – Apr 17 May 8 – May 22 Jun 27
Summer squash and zucchini Apr 10 – Apr 17 May 8 – May 22 Jun 22
Winter squash Apr 10 – Apr 17 May 8 – May 22 Jul 27
Sweet corn — May 1 – May 22 Jun 30
Onion (from sets) — Mar 26 – Apr 16 Jun 24
Garlic — Oct 3 – Oct 31 (fall) following summer
Spinach — Mar 22 – Apr 19 Apr 29
Basil Mar 27 – Apr 10 May 8 – May 22 Jul 4

Plan all 65 crops for Grand Coulee

Grand Coulee's weather over time

How the growing season has shifted here, year by year, from the station's own records.

Apr 1May 1Jun 1Jul 1 194019501960197019801990200020102020
Each year's last spring frostLong-term trend
See the data as a table
YearLast spring frost
1936Apr 6
1937Apr 7
1938Apr 2
1939Apr 6
1940Mar 13
1941Mar 23
1942Apr 23
1943Apr 25
1944Apr 18
1945Apr 28
1947Apr 7
1948May 2
1949May 4
1950Apr 26
1951Apr 21
1952Apr 29
1953Apr 15
1954May 2
1955May 14
1956Apr 8
1957Mar 28
1958Mar 27
1959May 5
1960Apr 24
1961Apr 20
1962Apr 29
1963Apr 10
1964May 14
1965May 6
1966Apr 19
1967Apr 30
1968Apr 24
1969Mar 26
1970Apr 27
1971Apr 18
1972Apr 30
1973Apr 19
1974May 17
1975Apr 21
1976Apr 25
1977Apr 19
1978Apr 12
1979Apr 21
1980Apr 10
1981May 5
1982May 9
1983Jul 4
1984Apr 25
1985May 12
1986Apr 30
1987Apr 19
1988Apr 10
1989Apr 3
1990Mar 26
1991Apr 26
1992Apr 23
1994Mar 25
1995Apr 19
1996May 8
1997Apr 12
1999May 10
2001Apr 14
2002May 8
2003Apr 16
2005Apr 28
2006Apr 18
2008May 1
2009Apr 24
2010May 7
2011Apr 29
2012Apr 29
2013May 1
2014Apr 28
2015Apr 26
2016Mar 19
2017Apr 16
2018Apr 18
2019Apr 29
2020Apr 16
2021Apr 12
2022May 8
2023Apr 20
2024Apr 30
2025Apr 17
2026Apr 27

What this means for you: Since 1936, Grand Coulee's last spring frost has come about 1 day later per decade, on average. The frost-free season has shrunk by about 2 days per decade. Year-to-year swings are large, so keep using the safe date rather than the trend.

Source: daily records from Coulee Dam 1 Sw (NOAA GHCN-Daily). Years with too many missing days are left out.

Nearby towns

Electric CityCoulee DamBridgeportBrewsterOkanoganOmak