Frost Dates for 82070 — Laramie, Wyoming

Half of springs at Laramie Regional Airport, WY see their last 32°F night by June 2; only one in ten is past it by May 21, and one in ten still has one after June 18. Planting tender crops after June 8 leaves a 30% risk of a frost on them, after June 11 20%, and after June 18 10%. The 16 days between the even-odds date and the one-in-ten date is wider than at 55% of the 33 Wyoming stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 15 in half of years, as early as September 3 one year in ten, and holds off past September 27 one year in ten. A hard freeze of 28°F follows 9 days later, around September 24; in spring the one-in-ten date for 28°F is June 3, 15 days before the 32°F one. The freeze-free season lasts 102 days in a typical year, shorter than at 79% of the 33 Wyoming stations; it reaches 120 days one year in ten and falls short of 84 one year in ten. On average 212 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 16 days longer, to about June 18, and return around September 4. Severe cold of 16°F or below comes every winter, usually between October 19 and April 23.

July is the warmest month at Laramie Regional Airport, WY, averaging 81°F by day and 49°F at night; December is the coldest at 33°F and 10°F. A freezing night is all but certain in every month from September to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 58% of years.

Warmth for growing adds up to 1,371 growing degree days a year (base 50°F), fewer than at 79% of the 33 Wyoming stations. 23% of them (320) have built up by the end of June, and July adds the most, 459. Precipitation totals 10.4 inches a year, most in May (1.8") and least in January (0.3"); May to September bring 65% of it.

The nearest other station, Laramie 2 NW, WY, 11 miles northeast of Laramie, has a last frost 5 days later (June 7), a first frost 11 days earlier (September 4), a season 14 days shorter.

The first measurable snow (0.1 inch or more) in Laramie usually arrives around October 10, and the last of the season around May 18. Those are the middle dates across the winters of 1991–2020 at Laramie 1.3 SE, WY, 10.3 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 15 days after the last snow.

ZIP 82070 is 7 miles from Laramie Regional Airport, WY, which stands at 7,266 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 82070 in zone 4b, the band where the coldest night of the year averaged -25 to -20°F (-31.7 to -28.9°C) over 1991–2020; a zone describes winter lows, not frost dates.