Frost Dates for 84534 — Montezuma Creek, Utah

Half of springs at Bluff, UT see their last 32°F night by April 24; only one in ten is past it by April 8, and one in ten still has one after May 9. Planting tender crops after April 30 leaves a 30% risk of a frost on them, after May 3 20%, and after May 9 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 89% of the 66 Utah stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 13 in half of years, as early as October 1 one year in ten, and holds off past October 28 one year in ten. A hard freeze of 28°F follows 10 days later, around October 23; in spring the one-in-ten date for 28°F is April 26, 13 days before the 32°F one. The freeze-free season lasts 172 days in a typical year, longer than at 64% of the 66 Utah stations; it reaches 193 days one year in ten and falls short of 153 one year in ten. On average 140 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 5, and return around October 4. Severe cold of 16°F or below comes every winter, usually between November 22 and February 18.

July is the warmest month at Bluff, UT, averaging 96°F by day and 64°F at night; December is the coldest at 43°F and 20°F. A freezing night is all but certain in every month from October 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 27% of years.

Warmth for growing adds up to 3,873 growing degree days a year (base 50°F), more than at 92% of the 66 Utah stations. 36% of them (1,379) have built up by the end of June, and July adds the most, 925. Precipitation totals 7.2 inches a year, most in August (0.9") and least in June (0.2"); May to September bring 42% of it.

The nearest other station, Teec Nos Pos, AZ, 24 miles southeast of Montezuma Creek and 971 feet higher, has a last frost 13 days earlier (April 11), a first frost 19 days later (November 1), a season 28 days longer.

The first measurable snow (0.1 inch or more) in Montezuma Creek usually arrives around December 9, and the last of the season around February 6. Those are the middle dates across the winters of 1991–2020 at Bluff, UT, 15.2 miles away: half of years saw snow earlier, half later. Snow fell in 93% of those winters. The last 32°F night of spring typically comes 77 days after the last snow.

ZIP 84534 is 15 miles from Bluff, UT, which stands at 4,319 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 84534 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.