Frost Dates for 81648 — Rangely, Colorado

Half of springs at Rangely 1E, CO see their last 32°F night by May 15; only one in ten is past it by May 2, and one in ten still has one after June 2. Planting tender crops after May 23 leaves a 30% risk of a frost on them, after May 27 20%, and after June 2 10%. The 18 days between the even-odds date and the one-in-ten date is wider than at 89% of the 110 Colorado stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 1 in half of years, as early as September 19 one year in ten, and holds off past October 12 one year in ten. A hard freeze of 28°F follows 9 days later, around October 10; in spring the one-in-ten date for 28°F is May 17, 16 days before the 32°F one. The freeze-free season lasts 136 days in a typical year, shorter than at 55% of the 110 Colorado stations; it reaches 154 days one year in ten and falls short of 115 one year in ten. On average 176 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 May 28, and return around September 23. Severe cold of 16°F or below comes every winter, usually between November 8 and March 20.

July is the warmest month at Rangely 1E, CO, averaging 93°F by day and 55°F at night; January is the coldest at 31°F and 3°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 2,640 growing degree days a year (base 50°F), more than at 55% of the 110 Colorado stations. 30% of them (787) have built up by the end of June, and July adds the most, 742. Precipitation totals 11.0 inches a year, most in September (1.3") and least in December (0.6"); May to September bring 45% of it.

The first measurable snow (0.1 inch or more) in Rangely usually arrives around November 11, and the last of the season around April 1. Those are the middle dates across the winters of 1991–2020 at Rangely 1E, CO, 5.4 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 44 days after the last snow.

ZIP 81648 is 5 miles from Rangely 1E, CO, which stands at 5,277 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 81648 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.