Frost Dates for 84627 — Ephraim, Utah

Half of springs at Ephraim, UT see their last 32°F night by May 28; only one in ten is past it by May 12, and one in ten still has one after June 15. Planting tender crops after June 4 leaves a 30% risk of a frost on them, after June 8 20%, and after June 15 10%. The 18 days between the even-odds date and the one-in-ten date is narrower than at 47% of the 66 Utah stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 20 in half of years, as early as September 5 one year in ten, and holds off past October 1 one year in ten. A hard freeze of 28°F follows 9 days later, around September 29; in spring the one-in-ten date for 28°F is May 31, 15 days before the 32°F one. The freeze-free season lasts 113 days in a typical year, shorter than at 85% of the 66 Utah stations; it reaches 133 days one year in ten and falls short of 93 one year in ten. On average 187 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 13, and return around September 11. Severe cold of 16°F or below comes every winter, usually between November 3 and March 19.

July is the warmest month at Ephraim, UT, averaging 91°F by day and 52°F at night; January is the coldest at 36°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 40% of years.

Warmth for growing adds up to 2,267 growing degree days a year (base 50°F), fewer than at 71% of the 66 Utah stations. 28% of them (626) have built up by the end of June, and July adds the most, 663. Precipitation totals 11.8 inches a year, most in May (1.3") and least in July (0.6"); May to September bring 39% of it.

The nearest other station, Manti Radio Kmti, UT, 7 miles southwest of Ephraim, has a last frost 3 days later (May 31), a first frost 1 day later (September 21), a season 1 day longer.

The first measurable snow (0.1 inch or more) in Ephraim usually arrives around December 1, and the last of the season around April 2. Those are the middle dates across the winters of 1991–2020 at Ephraim, UT, 1.2 miles away: half of years saw snow earlier, half later. Snow fell in 78% of those winters. The last 32°F night of spring typically comes 56 days after the last snow.

ZIP 84627 is 1 mile from Ephraim, UT, which stands at 5,498 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 84627 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.