Frost dates in Alaska

Across Alaska's 163 NOAA stations with a frost every year, the typical last spring frost ranges from April 4 at Beaver Falls (40 feet above sea level) to June 12 at Cooper Landing 5 W (370 feet above sea level). The middle station's date is May 16.

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Last frost across Alaska

The frost-free season runs from 73 days at Gulkana Airport to 218 days at Beaver Falls.

The station with the latest frost is about 350 miles farther north than the one with the earliest.

At 29 stations, all high or far north, frost is possible in every month.

These are typical dates: in half of springs the last frost comes later. Each place's page, and each ZIP code lookup, also gives the late-year date, after which only 1 spring in 10 has a frost. That's the safer date for tender plants.

Frost dates for Alaska's larger places

Typical (1-in-2) dates. Each place's page has the early and late years, a planting calendar and a printable planner. Zones are for the ZIP code nearest each place's center.

Hardiness zones in Alaska

Alaska's 272 ZIP codes in the USDA list fall in zones 1a to 8b: 1a (2 percent), 1b (4 percent), 2a (10 percent), 2b (6 percent), 3a (7 percent), 3b (10 percent), 4a (11 percent), 4b (10 percent), 5a (12 percent), 5b (6 percent), 6a (1 percent), 6b (3 percent), 7a (8 percent), 7b (6 percent), 8a (3 percent) and 8b (1 percent). Compared with the 2012 map, 53 percent of them moved to a warmer half zone (44 by a full zone or more), 38 percent stayed the same and 26 moved to a colder one.

A hardiness zone is about the coldest night of winter, which decides which shrubs, trees and perennials survive. Frost dates are about spring and fall, which decide when to plant. You need both. Read more about what the zones mean and what changed in 2023.

Every NOAA station in Alaska

All 192 stations in Alaska with frost statistics in NOAA's 1991 to 2020 normals, from A to Z. Station names are usually a town, an airport, or a distance and direction from a town. Find one near you and at a similar elevation.

Typical (1-in-2) dates at 32°F. For the early and late years, and a planting calendar built from your own dates, look up your ZIP code.