Anchorage, Alaska: freeze dates & growing season

Three different things get called “Anchorage” here, so this page is explicit about all three: the metro label (Anchorage), the anchor geography (Census ZCTA 99501, a downtown ZIP-code area), and the climate record (the NOAA station below). Windows are calculated from the station — not from your street address.

Climate basis: NOAA station Anchorage Merrill Fld, AK (USW00026409), 0 mi (0 km) from the ZCTA 99501 centroid, elevation 138 ft, on the 1991–2020 climate normals.

Last spring freezeMay 11-in-10 after May 9

First fall freezeSeptember 291-in-10 before Sep 17

Frost-free season≈ 150 daysmedian at 32°F

Hard freeze, 28°Apr 19 – Oct 8kills even hardy greens

USDA zone5a-20 to -15°F winter low — not frost timing

The year

indoors under lights
in the garden
frost-free season
1-in-10 years still freeze to May 9

The Anchorage year: hatched areas are the freeze-likely seasons in 1991–2020 normals.

What that means in practice

Tomatoes: plant May 8 – May 22
Peas: plant March 20 – April 3
Garlic: plant cloves October 6 – October 13

All 79 crops in Anchorage

These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.

Check a specific ZIP instead

Metro climates vary — elevation, water, and urban heat shift freeze dates by days to weeks. Look up your exact ZIP:

Nearby reviewed metros

Seattle, WA · Portland, OR · Spokane, WA · Boise, ID · Reno, NV