Frost Dates for 81652 — Silt, Colorado

Half of springs at Rifle Garfield Co Airport, CO see their last 32°F night by May 11; only one in ten is past it by April 28, and one in ten still has one after May 27. Planting tender crops after May 17 leaves a 30% risk of a frost on them, after May 21 20%, and after May 27 10%. The 16 days between the even-odds date and the one-in-ten date is wider than at 75% of the 110 Colorado stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 4 in half of years, as early as September 23 one year in ten, and holds off past October 17 one year in ten. A hard freeze of 28°F follows 11 days later, around October 15; in spring the one-in-ten date for 28°F is May 11, 16 days before the 32°F one. The freeze-free season lasts 143 days in a typical year, longer than at 51% of the 110 Colorado stations; it reaches 162 days one year in ten and falls short of 124 one year in ten. On average 173 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 15 days longer, to about May 26, and return around September 25. Severe cold of 16°F or below comes every winter, usually between November 13 and March 8.

July is the warmest month at Rifle Garfield Co Airport, CO, averaging 92°F by day and 55°F at night; January is the coldest at 37°F and 13°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 82% of years.

Warmth for growing adds up to 2,679 growing degree days a year (base 50°F), more than at 56% of the 110 Colorado stations. 31% of them (820) have built up by the end of June, and July adds the most, 735. Precipitation totals 10.8 inches a year, most in September (1.3") and least in February (0.6"); May to September bring 48% of it.

The nearest other station, Rifle 3ENE, CO, 5 miles northwest of Silt, has a last frost 12 days later (May 23), a first frost 9 days earlier (September 25), a season 19 days shorter.

The first measurable snow (0.1 inch or more) in Silt usually arrives around November 6, and the last of the season around April 15. Those are the middle dates across the winters of 1991–2020 at Rifle 3ENE, CO, 4.5 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 26 days after the last snow.

ZIP 81652 is 3 miles from Rifle Garfield Co Airport, CO, which stands at 5,530 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 81652 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.