Frost Dates for 82240 — Torrington, Wyoming

Half of springs at Torrington Exp Farm, WY see their last 32°F night by May 14; only one in ten is past it by May 2, and one in ten still has one after May 28. Planting tender crops after May 19 leaves a 30% risk of a frost on them, after May 23 20%, and after May 28 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 58% of the 33 Wyoming stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 24 in half of years, as early as September 10 one year in ten, and holds off past October 5 one year in ten. A hard freeze of 28°F follows 9 days later, around October 3; in spring the one-in-ten date for 28°F is May 17, 11 days before the 32°F one. The freeze-free season lasts 130 days in a typical year, longer than at 61% of the 33 Wyoming stations; it reaches 148 days one year in ten and falls short of 111 one year in ten. On average 190 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 26, and return around September 15. Severe cold of 16°F or below comes every winter, usually between October 30 and March 31.

July is the warmest month at Torrington Exp Farm, WY, averaging 90°F by day and 57°F at night; December is the coldest at 42°F and 12°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month.

Warmth for growing adds up to 2,606 growing degree days a year (base 50°F), more than at 94% of the 33 Wyoming stations. 31% of them (797) have built up by the end of June, and July adds the most, 716. Precipitation totals 14.9 inches a year, most in May (3.2") and least in January (0.3"); May to September bring 64% of it.

The nearest other station, Mitchell 5E, NE, 28 miles southeast of Torrington, has a last frost 7 days earlier (May 7), a first frost 8 days later (October 2), a season 17 days longer.

The first measurable snow (0.1 inch or more) in Torrington usually arrives around October 23, and the last of the season around April 15. Those are the middle dates across the winters of 1991–2020 at Torrington Exp Farm, WY, 3.1 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 29 days after the last snow.

ZIP 82240 is 3 miles from Torrington Exp Farm, WY, which stands at 4,098 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 82240 in zone 5a, the band where the coldest night of the year averaged -20 to -15°F (-28.9 to -26.1°C) over 1991–2020; a zone describes winter lows, not frost dates.