Frost Dates for 99712 — Fairbanks, Alaska

Half of springs at Fairbanks 11 NE, AK see their last 32°F night by May 12; only one in ten is past it by May 2, and one in ten still has one after May 29. Planting tender crops after May 19 leaves a 30% risk of a frost on them, after May 22 20%, and after May 29 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 89% of the 37 Alaska stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 16 in half of years, as early as August 29 one year in ten, and holds off past September 28 one year in ten. A hard freeze of 28°F follows 10 days later, around September 26; in spring the one-in-ten date for 28°F is May 17, 12 days before the 32°F one. The freeze-free season lasts 124 days in a typical year, shorter than at 59% of the 37 Alaska stations; it reaches 144 days one year in ten and falls short of 102 one year in ten. On average 209 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 12 days longer, to about May 24, and return around September 2. Severe cold of 16°F or below comes every winter, usually between October 18 and April 12.

July is the warmest month at Fairbanks 11 NE, AK, averaging 68°F by day and 51°F at night; January is the coldest at 10°F and -2°F. A freezing night is all but certain in every month from September to May (a 90% chance or more). From June to July the chance of a 32°F night stays under 10% each month.

Warmth for growing adds up to 786 growing degree days a year (base 50°F), more than at 62% of the 37 Alaska stations. 39% of them (308) have built up by the end of June, and July adds the most, 302. Precipitation totals 15.2 inches a year, most in July (2.9") and least in March (0.5"); May to September bring 70% of it.

The nearest other station, Aurora, AK, 8 miles southwest of Fairbanks and 697 feet lower, has a last frost 4 days later (May 16), a first frost 10 days earlier (September 6), a season 12 days shorter.

The first measurable snow (0.1 inch or more) in Fairbanks usually arrives around October 7, and the last of the season around April 8. Those are the middle dates across the winters of 1991–2020 at Gilmore Creek, AK, 3.6 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 34 days after the last snow.

ZIP 99712 is 3 miles from Fairbanks 11 NE, AK, which stands at 1,140 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 99712 in zone 3b, the band where the coldest night of the year averaged -35 to -30°F (-37.2 to -34.4°C) over 1991–2020; a zone describes winter lows, not frost dates.