Frost Dates for 81507 — Grand Junction, Colorado

Half of springs at Colorado Nm, CO see their last 32°F night by April 26; only one in ten is past it by April 9, and one in ten still has one after May 15. Planting tender crops after May 3 leaves a 30% risk of a frost on them, after May 8 20%, and after May 15 10%. The 19 days between the even-odds date and the one-in-ten date is wider than at 95% of the 110 Colorado stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 16 in half of years, as early as October 1 one year in ten, and holds off past November 3 one year in ten. A hard freeze of 28°F follows 13 days later, around October 29; in spring the one-in-ten date for 28°F is May 2, 13 days before the 32°F one. The freeze-free season lasts 172 days in a typical year, longer than at 97% of the 110 Colorado stations; it reaches 196 days one year in ten and falls short of 147 one year in ten. On average 128 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 7, and return around October 6. Severe cold of 16°F or below comes every winter, usually between November 29 and February 19.

July is the warmest month at Colorado Nm, CO, averaging 93°F by day and 65°F at night; January is the coldest at 39°F and 21°F. A freezing night is all but certain in every month from November 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 36% of years.

Warmth for growing adds up to 3,581 growing degree days a year (base 50°F), more than at 93% of the 110 Colorado stations. 33% of them (1,195) have built up by the end of June, and July adds the most, 889. Precipitation totals 11.3 inches a year, most in September (1.3") and least in February (0.6"); May to September bring 44% of it.

The nearest other station, Grand Junction 6ESE, CO, 11 miles east of Grand Junction and 1,021 feet lower, has a last frost 3 days earlier (April 23), a first frost 4 days later (October 20), a season 7 days longer.

The first measurable snow (0.1 inch or more) in Grand Junction usually arrives around November 24, and the last of the season around March 23. Those are the middle dates across the winters of 1991–2020 at Colorado Nm, CO, 8.7 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 34 days after the last snow.

ZIP 81507 is 9 miles from Colorado Nm, CO, which stands at 5,781 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 81507 in zone 7a, the band where the coldest night of the year averaged 0 to 5°F (-17.8 to -15.0°C) over 1991–2020; a zone describes winter lows, not frost dates.