Frost Dates for 82633 — Douglas, Wyoming

Half of springs at Douglas Converse Co Airport, WY see their last 32°F night by May 23; only one in ten is past it by May 10, and one in ten still has one after June 7. Planting tender crops after May 29 leaves a 30% risk of a frost on them, after June 1 20%, and after June 7 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 48% 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 9 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 24, 14 days before the 32°F one. The freeze-free season lasts 122 days in a typical year, shorter than at 58% of the 33 Wyoming stations; it reaches 140 days one year in ten and falls short of 102 one year in ten. On average 189 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 5, and return around September 12. Severe cold of 16°F or below comes every winter, usually between October 29 and April 3.

July is the warmest month at Douglas Converse Co Airport, WY, averaging 89°F by day and 55°F at night; December is the coldest at 38°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 22% of years.

Warmth for growing adds up to 2,282 growing degree days a year (base 50°F), more than at 76% of the 33 Wyoming stations. 27% of them (611) have built up by the end of June, and July adds the most, 678. Precipitation totals 11.3 inches a year, most in May (2.3") and least in January (0.3"); May to September bring 60% of it.

The first measurable snow (0.1 inch or more) in Douglas usually arrives around October 14, and the last of the season around May 2. Those are the middle dates across the winters of 1991–2020 at Douglas 1 SE, WY, 13.1 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 21 days after the last snow.

ZIP 82633 is 10 miles from Douglas Converse Co Airport, WY, which stands at 4,929 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 82633 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.