When is the last frost in Seattle, WA?

The average (50% probability) last spring frost in Seattle is March 2, based on NOAA 1991–2020 normals. A 1-in-10 risk remains until March 23.

When is the first frost in Seattle?

The average first fall frost in Seattle is November 23, with a growing season of about 266 days.

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Seattle, Washington frost dates

Average last spring frost: March 2. Average first fall frost: November 23. That gives a growing season of about 266 days. For frost-tender plants, a safer planting date is March 23, after which a freeze happens in only 1 year in 10.

Last frost (50%)

Mar 2

1-in-10 risk after Mar 23

First frost (50%)

Nov 23

1-in-10 risk before Nov 6

Growing season

266 days

median frost-free days

Hard freeze (28°F)

Feb 4

median last 28°F in spring

Frost risk by date

Chance of frost	Spring: frost after	Fall: frost before
90%	February 5	December 15
70%	February 22	December 2
50%	March 2	November 23
30%	March 12	November 14
10%	March 23	November 6

Read the spring column like this: there is a 10% chance of a 32°F freeze after March 23. These are NOAA probabilities for the Seattle Tacoma International Airport weather station (USW00024233, elevation 113 m), 1991–2020.

Seattle vegetable planting calendar

Dates count from the 50% last-frost date (March 2). For tomatoes, peppers and other frost-tender crops, waiting until the 10% date (Mar 23) is the cautious choice.

Crop	Start seeds indoors	Plant out
Beans	Feb 9	Mar 9 (usually sown directly in the garden)
Broccoli	Dec 22	Feb 2
Brussels sprouts	Dec 22	Feb 2
Cabbage	Dec 15	Jan 26
Cauliflower	Jan 5	Feb 16
Sweet corn	Feb 2	Mar 2 (usually sown directly in the garden)
Cucumbers	Feb 16	Mar 9
Kale	Dec 15	Jan 26
Leeks	Nov 17	Jan 26
Lettuce	Jan 12	Feb 16
Melons	Feb 23	Mar 16
Onions	Nov 10	Jan 19 (from seed; sets and transplants go out at the same time)
Peas	Jan 5	Feb 2 (usually sown directly in the garden)
Peppers	Jan 19	Mar 16
Squash	Feb 23	Mar 16
Tomatoes	Jan 5	Mar 2

Offsets from Oregon State University Extension's seed-starting table. "Plant out" means transplant, or sow directly for crops usually grown from seed.

Fall frost and season extension

The first fall freeze usually arrives around November 23. There's a 1-in-10 chance it comes before November 6. Harvest tender crops such as basil, tomatoes, peppers and squash before then, or cover them on cold nights. Cool-season crops like kale, cabbage and Brussels sprouts handle light frost, and often taste sweeter after it. A hard freeze (28°F) typically comes around December 10.

Nearby cities

City	Last frost (50%)	First frost (50%)	Distance
Yakima, WA	May 8	Oct 4	~165 km
Portland, OR	Mar 13	Nov 19	~207 km
Spokane, WA	Apr 26	Oct 12	~360 km
Eugene, OR	Apr 11	Oct 23	~374 km
Medford, OR	Apr 8	Oct 29	~564 km
Missoula, MT	May 16	Sep 26	~620 km

More: all Washington frost dates