Frost Dates for 84754 — Monroe, Utah

Half of springs at Koosharem, UT see their last 32°F night by June 6; only one in ten is past it by May 24, and one in ten still has one after June 26. Planting tender crops after June 14 leaves a 30% risk of a frost on them, after June 20 20%, and after June 26 10%. The 20 days between the even-odds date and the one-in-ten date is wider than at 61% of the 66 Utah stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 21 in half of years, as early as September 5 one year in ten, and holds off past October 2 one year in ten. A hard freeze of 28°F follows 8 days later, around September 29; in spring the one-in-ten date for 28°F is June 10, 16 days before the 32°F one. The freeze-free season lasts 104 days in a typical year, shorter than at 88% of the 66 Utah stations; it reaches 123 days one year in ten and falls short of 81 one year in ten. On average 221 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 16 days longer, to about June 22, and return around September 10. Severe cold of 16°F or below comes every winter, usually between October 31 and April 6.

July is the warmest month at Koosharem, UT, averaging 85°F by day and 48°F at night; December is the coldest at 39°F and 11°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 68% of years.

Warmth for growing adds up to 1,620 growing degree days a year (base 50°F), fewer than at 89% of the 66 Utah stations. 26% of them (422) have built up by the end of June, and July adds the most, 508. Precipitation totals 10.3 inches a year, most in August (1.4") and least in February (0.5"); May to September bring 51% of it.

The nearest other station, Richfield Radio Ksvc, UT, 14 miles northwest of Monroe and 1,645 feet lower, has a last frost 16 days earlier (May 21), a first frost 3 days later (September 24), a season 21 days longer.

The first measurable snow (0.1 inch or more) in Monroe usually arrives around November 6, and the last of the season around April 30. Those are the middle dates across the winters of 1991–2020 at Koosharem, UT, 7.6 miles away: half of years saw snow earlier, half later. Snow fell in 95% of those winters. The last 32°F night of spring typically comes 37 days after the last snow.

ZIP 84754 is 8 miles from Koosharem, UT, which stands at 6,930 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 84754 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.