Anchorage, AK 99513 Frost Dates
99513, near Anchorage, AK: the frost window
Typically, the last spring freeze lands around 05/01, roughly 246 days out. Fall's first freeze usually shows up around 09/29, roughly 150 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Anchorage in Zone 5b (-15 to -10°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
Anchorage's growing season runs out in roughly 5 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around Anchorage's last frost
05/01 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/19 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/09 and only about 1 year in 10 sees frost after that.
Anchorage against the rest of the dataset
Anchorage's growing season runs about 150 days, ranking 35,238 of 40,283 US ZIP codes measured here, longest to shortest. Within AK, it ranks 50 of 269.
Learn more
Two guides worth reading on 99513: zone vs. frost date, on why Zone 5b and Anchorage's frost date answer different questions, and the frost range, on how to read the range around Anchorage's dates instead of trusting one.