Frost Dates for 81416 — Delta, Colorado

Half of springs at Delta 3E, CO see their last 32°F night by May 1; only one in ten is past it by April 19, and one in ten still has one after May 14. Planting tender crops after May 5 leaves a 30% risk of a frost on them, after May 9 20%, and after May 14 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 7 in half of years, as early as September 26 one year in ten, and holds off past October 19 one year in ten. A hard freeze of 28°F follows 9 days later, around October 16; in spring the one-in-ten date for 28°F is May 3, 11 days before the 32°F one. The freeze-free season lasts 159 days in a typical year, longer than at 78% of the 110 Colorado stations; it reaches 175 days one year in ten and falls short of 142 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 13 days longer, to about May 14, and return around September 30. Severe cold of 16°F or below comes every winter, usually between November 16 and March 3.

July is the warmest month at Delta 3E, CO, averaging 93°F by day and 58°F at night; January is the coldest at 40°F and 15°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 52% of years.

Warmth for growing adds up to 3,082 growing degree days a year (base 50°F), more than at 81% of the 110 Colorado stations. 34% of them (1,041) have built up by the end of June, and July adds the most, 786.

The nearest other station, Cedaredge 3E, CO, 16 miles northeast of Delta and 1,811 feet higher, has a last frost 2 days later (May 3), a first frost 2 days later (October 9), a season 3 days shorter.

The first measurable snow (0.1 inch or more) in Delta usually arrives around November 30, and the last of the season around March 3. Those are the middle dates across the winters of 1991–2020 at Delta 3E, CO, 3.2 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 59 days after the last snow.

ZIP 81416 is 3 miles from Delta 3E, CO, which stands at 5,027 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 81416 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.