Anchorage, AK 99505 Frost Dates
When can you plant in Anchorage, AK?
Around 05/09 is the usual last spring frost, about 254 days away. The first fall frost typically arrives around 09/26, about 138 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.
How much risk comes with planting early here
05/09 is the middle of 30 years of NOAA records, not a promise. Plant by 04/28 and you're betting against frost in roughly 9 years out of 10. 05/22 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Anchorage compares
At roughly 138 frost-free days, Anchorage places 37,334 of 40,283 ZIP codes in this dataset. Within AK, it ranks 69 of 269.
Learn more
local microclimates covers what one yard in Anchorage can differ from the 99505 normal. zone vs. frost date covers why Zone 5a and Anchorage's frost date answer different questions.