Anchorage, AK 99518 Frost Dates
Frost dates for Anchorage, AK, ZIP 99518
Typically, the last spring freeze lands around 05/01, roughly 246 days out. The first fall frost typically arrives around 10/03, about 156 frost-free days later.
Zone 5a (-20 to -15°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Anchorage, not a forecast for this year.
What to do before the first frost
Zone 5a around Anchorage has about 5 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
The actual range around Anchorage's last frost
05/01 is the middle of 30 years of NOAA records, not a promise. Plant by 04/20 and you're betting against frost in roughly 9 years out of 10. 05/08 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Anchorage compares
Anchorage's growing season runs about 156 days, ranking 33,486 of 40,283 US ZIP codes measured here, longest to shortest. Within AK, it ranks 39 of 269.
Learn more
the frost range explains how to read the range around Anchorage's dates instead of trusting one, and local microclimates explains what one yard in Anchorage can differ from the 99518 normal.