Frost Dates for 81137 — Ignacio, Colorado

Half of springs at Ignacio 6ESE, CO see their last 32°F night by May 23; only one in ten is past it by May 9, and one in ten still has one after June 7. Planting tender crops after May 30 leaves a 30% risk of a frost on them, after June 2 20%, and after June 7 10%. The 15 days between the even-odds date and the one-in-ten date is wider than at 56% of the 110 Colorado stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 29 in half of years, as early as September 18 one year in ten, and holds off past October 11 one year in ten. A hard freeze of 28°F follows 9 days later, around October 8; in spring the one-in-ten date for 28°F is May 23, 15 days before the 32°F one. The freeze-free season lasts 128 days in a typical year, shorter than at 60% of the 110 Colorado stations; it reaches 147 days one year in ten and falls short of 109 one year in ten. On average 202 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 21. Severe cold of 16°F or below comes every winter, usually between November 8 and March 31.

July is the warmest month at Ignacio 6ESE, CO, averaging 86°F by day and 52°F at night; January is the coldest at 38°F and 11°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 24% of years.

Warmth for growing adds up to 2,011 growing degree days a year (base 50°F), fewer than at 62% of the 110 Colorado stations. 28% of them (561) have built up by the end of June, and July adds the most, 587. Precipitation totals 13.7 inches a year, most in September (2.0") and least in June (0.4"); May to September bring 47% of it.

The nearest other station, Durango La Plata Co Airport, CO, 7 miles northwest of Ignacio, has a last frost 9 days later (June 1), a first frost 2 days earlier (September 27), a season 12 days shorter.

The first measurable snow (0.1 inch or more) in Ignacio usually arrives around November 20, and the last of the season around April 12. Those are the middle dates across the winters of 1991–2020 at Ignacio 6ESE, CO, 6.1 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 41 days after the last snow.

ZIP 81137 is 6 miles from Ignacio 6ESE, CO, which stands at 6,548 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 81137 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.