Thorne Bay, AK 99919 Frost Dates
Frost dates for Thorne Bay, AK, ZIP 99919
The last spring frost here typically falls around 05/01, about 246 days from today. The first fall frost typically arrives around 10/13, about 166 frost-free days later.
Zone 7b (5 to 10°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 Thorne Bay, not a forecast for this year.
What to do before the first frost
Zone 7b around Thorne Bay has about 7 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.
How much risk comes with planting early here
05/01 is the middle of 30 years of NOAA records, not a promise. Plant by 04/17 and you're betting against frost in roughly 9 years out of 10. 05/16 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Thorne Bay compares
Thorne Bay's growing season runs about 166 days, ranking 30,434 of 40,283 US ZIP codes measured here, longest to shortest. Within AK, it ranks 23 of 269.
Learn more
zone vs. frost date explains why Zone 7b and Thorne Bay's frost date answer different questions, and the frost range explains how to read the range around Thorne Bay's dates instead of trusting one.