Frost Dates for 84333 — Richmond, Utah

Half of springs at Richmond, UT see their last 32°F night by May 11; only one in ten is past it by April 27, and one in ten still has one after June 2. Planting tender crops after May 20 leaves a 30% risk of a frost on them, after May 25 20%, and after June 2 10%. The 22 days between the even-odds date and the one-in-ten date is wider than at 80% of the 66 Utah stations behind this site's ZIP pages, so a fixed calendar date is a gamble here.

In fall the first 32°F night comes by October 5 in half of years, as early as September 21 one year in ten, and holds off past October 20 one year in ten. A hard freeze of 28°F follows 12 days later, around October 17; in spring the one-in-ten date for 28°F is May 13, 20 days before the 32°F one. The freeze-free season lasts 143 days in a typical year, shorter than at 61% of the 66 Utah stations; it reaches 164 days one year in ten and falls short of 120 one year in ten. On average 155 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 20 days longer, to about May 31, and return around September 24. Severe cold of 16°F or below comes every winter, usually between November 18 and March 5.

July is the warmest month at Richmond, UT, averaging 89°F by day and 56°F at night; January is the coldest at 31°F and 17°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 81% of years and June still brings one in 12% of years.

Warmth for growing adds up to 2,451 growing degree days a year (base 50°F), fewer than at 67% of the 66 Utah stations. 26% of them (637) have built up by the end of June, and July adds the most, 705. Precipitation totals 20.4 inches a year, most in May (2.6") and least in July (0.6"); May to September bring 34% of it.

The nearest other station, Trenton, UT, 5 miles west of Richmond and 225 feet lower, has a last frost 6 days later (May 17), a first frost 17 days earlier (September 18), a season 22 days shorter.

The first measurable snow (0.1 inch or more) in Richmond usually arrives around November 5, and the last of the season around April 17. Those are the middle dates across the winters of 1991–2020 at Richmond, UT, 1 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 24 days after the last snow.

ZIP 84333 is 1 mile from Richmond, UT, which stands at 4,680 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 84333 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.