Anchorage, AK 99509 Frost Dates
When can you plant in Anchorage, AK?
Typically, the last spring freeze lands around 05/18, roughly 263 days out. The first fall frost typically arrives around 09/23, about 125 frost-free days later.
The USDA Plant Hardiness Zone Map puts Anchorage in Zone 5a (-20 to -15°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
About 4 weeks of growing season left in Anchorage before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Anchorage's last frost
05/18 is the middle of 30 years of NOAA records, not a promise. Plant by 05/04 and you're betting against frost in roughly 9 years out of 10. 05/31 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Anchorage compares
About 125 days separate Anchorage's last and first frost, putting it 38,737 of 40,283 ZIP codes nationally. Within AK, it ranks 86 of 269.
Learn more
the frost range covers how to read the range around Anchorage's dates instead of trusting one. local microclimates covers what one yard in Anchorage can differ from the 99509 normal.