Frost Dates for 82801 — Sheridan, Wyoming

Half of springs at Sheridan Co Airport, WY see their last 32°F night by May 21; only one in ten is past it by May 7, and one in ten still has one after June 6. Planting tender crops after May 27 leaves a 30% risk of a frost on them, after May 31 20%, and after June 6 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 23 in half of years, as early as September 9 one year in ten, and holds off past October 6 one year in ten. A hard freeze of 28°F follows 10 days later, around October 3; in spring the one-in-ten date for 28°F is May 22, 15 days before the 32°F one. The freeze-free season lasts 123 days in a typical year, shorter than at 52% of the 33 Wyoming stations; it reaches 143 days one year in ten and falls short of 102 one year in ten. On average 185 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 14 days longer, to about June 4, and return around September 13. Severe cold of 16°F or below comes every winter, usually between October 30 and April 2.

July is the warmest month at Sheridan Co Airport, WY, averaging 88°F by day and 54°F at night; January is the coldest at 36°F and 12°F. A freezing night is all but certain in every month from October 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 19% of years.

Warmth for growing adds up to 2,136 growing degree days a year (base 50°F), more than at 55% of the 33 Wyoming stations. 25% of them (540) have built up by the end of June, and July adds the most, 640. Precipitation totals 15.1 inches a year, most in May (2.7") and least in December (0.5"); May to September bring 53% of it.

The nearest other station, Buffalo, WY, 34 miles southeast of Sheridan and 694 feet higher, has a last frost 3 days later (May 24), a first frost 2 days earlier (September 21), a season 5 days shorter.

The first measurable snow (0.1 inch or more) in Sheridan usually arrives around November 7, and the last of the season around April 14. Those are the middle dates across the winters of 1991–2020 at Sheridan Field Stn, WY, 6.9 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 37 days after the last snow.

ZIP 82801 is 2 miles from Sheridan Co Airport, WY, which stands at 3,945 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 82801 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.