Frost Dates for 84721 — Cedar City, Utah

Half of springs at New Harmony, UT see their last 32°F night by May 9; only one in ten is past it by April 23, and one in ten still has one after May 29. Planting tender crops after May 17 leaves a 30% risk of a frost on them, after May 22 20%, and after May 29 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 October 11 in half of years, as early as September 27 one year in ten, and holds off past October 25 one year in ten. A hard freeze of 28°F follows 11 days later, around October 22; in spring the one-in-ten date for 28°F is May 13, 16 days before the 32°F one. The freeze-free season lasts 155 days in a typical year, shorter than at 52% of the 66 Utah stations; it reaches 175 days one year in ten and falls short of 131 one year in ten. On average 148 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 17 days longer, to about May 26, and return around October 1. Severe cold of 16°F or below comes every winter, usually between November 24 and February 26.

July is the warmest month at New Harmony, UT, averaging 90°F by day and 58°F at night; December is the coldest at 44°F and 21°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 69% of years.

Warmth for growing adds up to 2,837 growing degree days a year (base 50°F), more than at 50% of the 66 Utah stations. 30% of them (837) have built up by the end of June, and July adds the most, 736. Precipitation totals 17.4 inches a year, most in February (2.5") and least in June (0.4"); May to September bring 30% of it.

The nearest other station, Cedar City Municipal Airport, UT, 15 miles east of Cedar City and 419 feet higher, has a last frost 12 days later (May 21), a first frost 12 days earlier (September 29), a season 25 days shorter.

The first measurable snow (0.1 inch or more) in Cedar City usually arrives around November 25, and the last of the season around March 28. Those are the middle dates across the winters of 1991–2020 at New Harmony, UT, 14 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 42 days after the last snow.

ZIP 84721 is 14 miles from New Harmony, UT, which stands at 5,167 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 84721 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.