Frost Dates for 81635 — Parachute, Colorado

Half of springs at Altenbern, CO see their last 32°F night by May 25; only one in ten is past it by May 10, and one in ten still has one after June 13. Planting tender crops after June 2 leaves a 30% risk of a frost on them, after June 6 20%, and after June 13 10%. The 19 days between the even-odds date and the one-in-ten date is wider than at 95% of the 110 Colorado stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 25 in half of years, as early as September 10 one year in ten, and holds off past October 8 one year in ten. A hard freeze of 28°F follows 9 days later, around October 4; in spring the one-in-ten date for 28°F is May 29, 15 days before the 32°F one. The freeze-free season lasts 120 days in a typical year, shorter than at 65% of the 110 Colorado stations; it reaches 143 days one year in ten and falls short of 98 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 14 days longer, to about June 8, and return around September 15. Severe cold of 16°F or below comes every winter, usually between November 5 and March 23.

July is the warmest month at Altenbern, CO, averaging 90°F by day and 51°F at night; January is the coldest at 37°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 35% of years.

Warmth for growing adds up to 2,217 growing degree days a year (base 50°F), fewer than at 57% of the 110 Colorado stations. 29% of them (652) have built up by the end of June, and July adds the most, 631. Precipitation totals 17.3 inches a year, most in September (1.9") and least in June (0.8"); May to September bring 43% of it.

The nearest other station, Rifle Garfield Co Airport, CO, 21 miles east of Parachute, has a last frost 14 days earlier (May 11), a first frost 9 days later (October 4), a season 23 days longer.

The first measurable snow (0.1 inch or more) in Parachute usually arrives around November 3, and the last of the season around April 10. Those are the middle dates across the winters of 1991–2020 at Altenbern, CO, 14.1 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 45 days after the last snow.

ZIP 81635 is 14 miles from Altenbern, CO, which stands at 5,637 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 81635 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.