Anchorage, AK 99577 Frost Dates
Anchorage, AK: when does the frost end?
The last spring frost here typically falls around 05/09, about 254 days from today. Fall's first freeze usually shows up around 09/26, roughly 139 days after the last spring frost.
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.
Stretching the season past the first frost
With roughly 4 weeks until Anchorage's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 05/09 isn't a guarantee
05/09 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/29 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/22 and only about 1 year in 10 sees frost after that.
Anchorage against the rest of the dataset
At roughly 139 frost-free days, Anchorage places 37,201 of 40,283 ZIP codes in this dataset. Within AK, it ranks 68 of 269.
Learn more
Before leaning on 99577's figures: zone vs. frost date explains why Zone 5a and Anchorage's frost date answer different questions, while the frost range explains how to read the range around Anchorage's dates instead of trusting one.