Frost Dates for 80433 — Conifer, Colorado

Half of springs at Evergreen, 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 10. Planting tender crops after May 29 leaves a 30% risk of a frost on them, after June 2 20%, and after June 10 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 September 22 in half of years, as early as September 6 one year in ten, and holds off past October 3 one year in ten. A hard freeze of 28°F follows 10 days later, around October 2; in spring the one-in-ten date for 28°F is May 22, 19 days before the 32°F one. The freeze-free season lasts 118 days in a typical year, shorter than at 68% of the 110 Colorado stations; it reaches 138 days one year in ten and falls short of 95 one year in ten. On average 215 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 18 days longer, to about June 10, and return around September 11. Severe cold of 16°F or below comes every winter, usually between October 30 and April 12.

July is the warmest month at Evergreen, CO, averaging 81°F by day and 49°F at night; December is the coldest at 44°F and 13°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 23% of years.

Warmth for growing adds up to 1,514 growing degree days a year (base 50°F), fewer than at 78% of the 110 Colorado stations. 26% of them (393) have built up by the end of June, and July adds the most, 468. Precipitation totals 18.7 inches a year, most in May (2.5") and least in January (0.6"); May to September bring 55% of it.

The nearest other station, Bailey, CO, 12 miles southwest of Conifer and 767 feet higher, has a last frost 24 days later (June 16), a first frost 14 days earlier (September 8), a season 34 days shorter.

The first measurable snow (0.1 inch or more) in Conifer usually arrives around October 6, and the last of the season around May 15. Those are the middle dates across the winters of 1991–2020 at Evergreen 5.3 S, CO, 2.9 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 8 days after the last snow.

ZIP 80433 is 9 miles from Evergreen, CO, which stands at 6,985 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 80439 (Evergreen). The 2023 USDA Plant Hardiness Zone Map lists ZIP 80433 in zone 5b, the band where the coldest night of the year averaged -15 to -10°F (-26.1 to -23.3°C) over 1991–2020; a zone describes winter lows, not frost dates.