Frost Dates for 80247 — Denver, Colorado

Half of springs at Denver-Stapleton, CO see their last 32°F night by May 4; only one in ten is past it by April 20, and one in ten still has one after May 16. Planting tender crops after May 8 leaves a 30% risk of a frost on them, after May 11 20%, and after May 16 10%. The 12 days between the even-odds date and the one-in-ten date is narrower than at 81% of the 110 Colorado stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 8 in half of years, as early as September 25 one year in ten, and holds off past October 20 one year in ten. A hard freeze of 28°F follows 10 days later, around October 18; in spring the one-in-ten date for 28°F is May 7, 9 days before the 32°F one. The freeze-free season lasts 156 days in a typical year, longer than at 73% of the 110 Colorado stations; it reaches 175 days one year in ten and falls short of 138 one year in ten. On average 156 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 8 days longer, to about May 12, and return around October 1. Severe cold of 16°F or below comes every winter, usually between November 16 and March 15.

July is the warmest month at Denver-Stapleton, CO, averaging 90°F by day and 59°F at night; December is the coldest at 46°F and 18°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 64% of years.

Warmth for growing adds up to 3,011 growing degree days a year (base 50°F), more than at 77% of the 110 Colorado stations. 31% of them (944) have built up by the end of June, and July adds the most, 767. Precipitation totals 15.4 inches a year, most in May (2.3") and least in January (0.5"); May to September bring 61% of it.

The nearest other station, Cherry Creek Dam, CO, 5 miles southeast of Denver and 361 feet higher, has a last frost 3 days later (May 7), the same first-frost date, a season 4 days shorter.

The first measurable snow (0.1 inch or more) in Denver usually arrives around October 13, and the last of the season around April 30. Those are the middle dates across the winters of 1991–2020 at Denver-Stapleton, CO, 4.8 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 4 days after the last snow.

ZIP 80247 is 5 miles from Denver-Stapleton, CO, which stands at 5,286 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 9 other ZIP codes share the station; its figures are presented in full for 80022 (Commerce City). The 2023 USDA Plant Hardiness Zone Map lists ZIP 80247 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.