Frost Dates for 82201 — Wheatland, Wyoming

Half of springs at Wheatland 4 N, WY see their last 32°F night by May 19; only one in ten is past it by May 7, and one in ten still has one after June 2. Planting tender crops after May 24 leaves a 30% risk of a frost on them, after May 28 20%, and after June 2 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 22 in half of years, as early as September 8 one year in ten, and holds off past October 4 one year in ten. A hard freeze of 28°F follows 9 days later, around October 1; in spring the one-in-ten date for 28°F is May 22, 11 days before the 32°F one. The freeze-free season lasts 125 days in a typical year, longer than at 55% of the 33 Wyoming stations; it reaches 142 days one year in ten and falls short of 104 one year in ten. On average 153 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 13 days longer, to about June 1, and return around September 12. Severe cold of 16°F or below comes every winter, usually between October 28 and April 4.

July is the warmest month at Wheatland 4 N, WY, averaging 90°F by day and 54°F at night; December is the coldest at 43°F and 16°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 13% of years.

Warmth for growing adds up to 2,546 growing degree days a year (base 50°F), more than at 88% of the 33 Wyoming stations. 29% of them (742) have built up by the end of June, and July adds the most, 688. Precipitation totals 14.1 inches a year, most in May (2.7") and least in January (0.3"); May to September bring 64% of it.

The first measurable snow (0.1 inch or more) in Wheatland usually arrives around October 16, and the last of the season around May 1. Those are the middle dates across the winters of 1991–2020 at Wheatland 4 N, WY, 7.2 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 18 days after the last snow.

ZIP 82201 is 7 miles from Wheatland 4 N, WY, which stands at 4,638 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 82201 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.