Frost Dates for 81052 — Lamar, Colorado

Half of springs at Lamar, CO see their last 32°F night by April 30; only one in ten is past it by April 17, and one in ten still has one after May 13. Planting tender crops after May 5 leaves a 30% risk of a frost on them, after May 8 20%, and after May 13 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 67% of the 110 Colorado stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 10 in half of years, as early as October 1 one year in ten, and holds off past October 21 one year in ten. A hard freeze of 28°F follows 10 days later, around October 20; in spring the one-in-ten date for 28°F is May 2, 11 days before the 32°F one. The freeze-free season lasts 163 days in a typical year, longer than at 87% of the 110 Colorado stations; it reaches 181 days one year in ten and falls short of 145 one year in ten. On average 160 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 10 days longer, to about May 10, and return around October 4. Severe cold of 16°F or below comes every winter, usually between November 15 and March 13.

July is the warmest month at Lamar, CO, averaging 93°F by day and 63°F at night; January is the coldest at 45°F and 14°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 47% of years.

Warmth for growing adds up to 3,676 growing degree days a year (base 50°F), more than at 96% of the 110 Colorado stations. 35% of them (1,288) have built up by the end of June, and July adds the most, 871. Precipitation totals 16.2 inches a year, most in July (2.8") and least in January (0.3"); May to September bring 69% of it.

The nearest other station, Las Animas, CO, 32 miles west of Lamar and 263 feet higher, has a last frost 1 day earlier (April 29), a first frost 2 days later (October 12), a season 3 days longer.

The first measurable snow (0.1 inch or more) in Lamar usually arrives around November 22, and the last of the season around March 25. Those are the middle dates across the winters of 1991–2020 at Lamar, CO, 0.8 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 36 days after the last snow.

ZIP 81052 is under a mile from Lamar, CO, which stands at 3,627 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 81052 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.