When is the last frost in Anchorage, AK?

The average (50% probability) last spring frost in Anchorage is May 5, based on NOAA 1991–2020 normals. A 1-in-10 risk remains until May 15.

When is the first frost in Anchorage?

The average first fall frost in Anchorage is October 1, with a growing season of about 147 days.

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Anchorage, Alaska frost dates

Average last spring frost: May 5. Average first fall frost: October 1. That gives a growing season of about 147 days. For frost-tender plants, a safer planting date is May 15, after which a freeze happens in only 1 year in 10.

Last frost (50%)

May 5

1-in-10 risk after May 15

First frost (50%)

Oct 1

1-in-10 risk before Sep 18

Growing season

147 days

median frost-free days

Hard freeze (28°F)

Apr 22

median last 28°F in spring

Frost risk by date

Chance of frost	Spring: frost after	Fall: frost before
90%	April 24	October 14
70%	May 1	October 6
50%	May 5	October 1
30%	May 9	September 26
10%	May 15	September 18

Read the spring column like this: there is a 10% chance of a 32°F freeze after May 15. These are NOAA probabilities for the Anchorage International Airport weather station (USW00026451, elevation 37 m), 1991–2020.

Anchorage vegetable planting calendar

Dates count from the 50% last-frost date (May 5). For tomatoes, peppers and other frost-tender crops, waiting until the 10% date (May 15) is the cautious choice.

Crop	Start seeds indoors	Plant out
Beans	Apr 14	May 12 (usually sown directly in the garden)
Broccoli	Feb 24	Apr 7
Brussels sprouts	Feb 24	Apr 7
Cabbage	Feb 17	Mar 31
Cauliflower	Mar 10	Apr 21
Sweet corn	Apr 7	May 5 (usually sown directly in the garden)
Cucumbers	Apr 21	May 12
Kale	Feb 17	Mar 31
Leeks	Jan 20	Mar 31
Lettuce	Mar 17	Apr 21
Melons	Apr 28	May 19
Onions	Jan 13	Mar 24 (from seed; sets and transplants go out at the same time)
Peas	Mar 10	Apr 7 (usually sown directly in the garden)
Peppers	Mar 24	May 19
Squash	Apr 28	May 19
Tomatoes	Mar 10	May 5

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 October 1. There's a 1-in-10 chance it comes before September 18. 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 October 10.

Nearby cities

City	Last frost (50%)	First frost (50%)	Distance
Seattle, WA	Mar 2	Nov 23	~2126 km
Yakima, WA	May 8	Oct 4	~2262 km
Portland, OR	Mar 13	Nov 19	~2268 km
Spokane, WA	Apr 26	Oct 12	~2299 km
Eugene, OR	Apr 11	Oct 23	~2374 km
Missoula, MT	May 16	Sep 26	~2490 km

More: all Alaska frost dates