Anchorage, AK Frost Dates & Growing Season

The two dates every Anchorage garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
May 1
~50% chance of frost after
First fall frost
Sep 29
~50% chance of frost before
Growing season
151 days
frost-free stretch
USDA zone
4b
2023 hardiness map
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Apr 19 May 1 May 9
First fall frost Oct 12 Sep 29 Sep 17
Hard freeze (28°F), median last Apr 19 · first Oct 8

Computed from NOAA 1991–2020 climate normals at the Anchorage Merrill Field station (2 km from central Anchorage). "Safe" means frost past that date happens only about one year in ten. Your exact garden can still run days either way with elevation and terrain — check your own ZIP with the frost date lookup.

Planting windows for Anchorage

Computed from Anchorage's own frost dates. Click any crop for the full zone-4 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Mar 6 – Mar 20 May 8 – May 15
🫑 Peppers Feb 20 – Mar 6 May 15 – May 22
🥬 Lettuce Mar 20 – Apr 3 Apr 3 – Apr 17 Apr 3 – May 1
🫛 Peas Mar 20 – Apr 3
🥕 Carrots Apr 10 – May 1
🥦 Broccoli Mar 13 – Mar 27 Apr 10 – Apr 24
🥬 Kale Mar 20 – Apr 3 Apr 3 – Apr 17 Apr 3 – Apr 17
🥒 Cucumbers Apr 3 – Apr 10 May 8 – May 15 May 8 – May 15
🥒 Zucchini Apr 3 – Apr 10 May 8 – May 15 May 8 – May 15
🫘 Green Beans (Bush) May 8 – May 15
🌽 Sweet Corn May 8 – May 15
🌿 Basil Mar 20 – Apr 3 May 8 – May 15 May 15 – May 22
🧄 Garlic Fall: Aug 18 – Sep 15

Want this for all 50 crops, or as a printable seed-shelf schedule? Use the planting calendar and the seed starting scheduler — both can use Anchorage's dates automatically after a lookup.

Reading the season in Anchorage

Roughly 151 frost-free days gives Anchorage gardeners room for nearly every common vegetable. Warm-season crops go out after May 1; a fall garden sown in late summer matures comfortably before the Sep 29 frost.

Frequently asked questions

When is the last frost in Anchorage, AK?

The average last spring frost in Anchorage is around May 1, based on 1991–2020 climate normals. That's a median — about half of years see a later frost, so tender crops are safest going out a week or two after this date.

When is the first frost in Anchorage, AK?

The average first fall frost in Anchorage arrives around Sep 29. Crops still in the garden need to mature before then, and frost-tender plants need harvesting or protection as the date approaches.

How long is the growing season in Anchorage?

About 151 frost-free days on average, from May 1 to Sep 29. That fits nearly all common vegetables, though the longest-season melons and sweet potatoes benefit from transplants.

What USDA zone is Anchorage in?

USDA zone 4b on the 2023 Plant Hardiness Zone Map. Note that zones describe winter cold, not frost timing — these frost dates are the numbers to plan plantings around.