Frost Dates for 80103 — Byers, Colorado

Half of springs at Byers 5 ENE, CO see their last 32°F night by May 13; only one in ten is past it by April 30, and one in ten still has one after May 30. Planting tender crops after May 18 leaves a 30% risk of a frost on them, after May 23 20%, and after May 30 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 85% of the 110 Colorado stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 2 in half of years, as early as September 20 one year in ten, and holds off past October 14 one year in ten. A hard freeze of 28°F follows 8 days later, around October 10; in spring the one-in-ten date for 28°F is May 15, 15 days before the 32°F one. The freeze-free season lasts 142 days in a typical year, shorter than at 50% of the 110 Colorado stations; it reaches 159 days one year in ten and falls short of 123 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 11 days longer, to about May 24, and return around September 25. Severe cold of 16°F or below comes every winter, usually between November 3 and March 30.

July is the warmest month at Byers 5 ENE, CO, averaging 90°F by day and 57°F at night; December is the coldest at 43°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 August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 88% of years.

Warmth for growing adds up to 2,725 growing degree days a year (base 50°F), more than at 60% of the 110 Colorado stations. 30% of them (819) have built up by the end of June, and July adds the most, 727. Precipitation totals 16.5 inches a year, most in July (2.6") and least in January (0.5"); May to September bring 62% of it.

The nearest other station, Denver International Airport, CO, 26 miles west of Byers and 313 feet higher, has a last frost 8 days earlier (May 5), a first frost 7 days later (October 9), a season 14 days longer.

The first measurable snow (0.1 inch or more) in Byers usually arrives around October 20, and the last of the season around April 26. Those are the middle dates across the winters of 1991–2020 at Byers 5 ENE, CO, 2.4 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 17 days after the last snow.

ZIP 80103 is 2 miles from Byers 5 ENE, CO, which stands at 5,101 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 80136 (Strasburg). The 2023 USDA Plant Hardiness Zone Map lists ZIP 80103 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.