When is the last frost in Portland, OR?

The average (50% probability) last spring frost in Portland is March 13, based on NOAA 1991–2020 normals. A 1-in-10 risk remains until April 1.

When is the first frost in Portland?

The average first fall frost in Portland is November 19, with a growing season of about 247 days.

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Portland, Oregon frost dates

Average last spring frost: March 13. Average first fall frost: November 19. That gives a growing season of about 247 days. For frost-tender plants, a safer planting date is April 1, after which a freeze happens in only 1 year in 10.

Last frost (50%)

Mar 13

1-in-10 risk after Apr 1

First frost (50%)

Nov 19

1-in-10 risk before Oct 29

Growing season

247 days

median frost-free days

Hard freeze (28°F)

Feb 16

median last 28°F in spring

Frost risk by date

Chance of frost	Spring: frost after	Fall: frost before
90%	February 22	December 10
70%	March 6	November 27
50%	March 13	November 19
30%	March 21	November 11
10%	April 1	October 29

Read the spring column like this: there is a 10% chance of a 32°F freeze after April 1. These are NOAA probabilities for the Portland International Airport weather station (USW00024229, elevation 6 m), 1991–2020.

Portland vegetable planting calendar

Dates count from the 50% last-frost date (March 13). For tomatoes, peppers and other frost-tender crops, waiting until the 10% date (Apr 1) is the cautious choice.

Crop	Start seeds indoors	Plant out
Beans	Feb 20	Mar 20 (usually sown directly in the garden)
Broccoli	Jan 2	Feb 13
Brussels sprouts	Jan 2	Feb 13
Cabbage	Dec 26	Feb 6
Cauliflower	Jan 16	Feb 27
Sweet corn	Feb 13	Mar 13 (usually sown directly in the garden)
Cucumbers	Feb 27	Mar 20
Kale	Dec 26	Feb 6
Leeks	Nov 28	Feb 6
Lettuce	Jan 23	Feb 27
Melons	Mar 6	Mar 27
Onions	Nov 21	Jan 30 (from seed; sets and transplants go out at the same time)
Peas	Jan 16	Feb 13 (usually sown directly in the garden)
Peppers	Jan 30	Mar 27
Squash	Mar 6	Mar 27
Tomatoes	Jan 16	Mar 13

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 19. There's a 1-in-10 chance it comes before October 29. 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 5.

Nearby cities

City	Last frost (50%)	First frost (50%)	Distance
Eugene, OR	Apr 11	Oct 23	~169 km
Yakima, WA	May 8	Oct 4	~193 km
Seattle, WA	Mar 2	Nov 23	~207 km
Medford, OR	Apr 8	Oct 29	~357 km
Spokane, WA	Apr 26	Oct 12	~454 km
Boise, ID	Apr 24	Oct 21	~543 km

More: all Oregon frost dates