Frost Dates for 84401 — Ogden, Utah

Half of springs at Ogden Pioneer Ph, UT see their last 32°F night by April 21; only one in ten is past it by April 2, and one in ten still has one after May 6. Planting tender crops after April 28 leaves a 30% risk of a frost on them, after May 1 20%, and after May 6 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 23 in half of years, as early as October 8 one year in ten, and holds off past November 6 one year in ten. A hard freeze of 28°F follows 11 days later, around November 3; in spring the one-in-ten date for 28°F is April 21, 15 days before the 32°F one. The freeze-free season lasts 184 days in a typical year, longer than at 83% of the 66 Utah stations; it reaches 208 days one year in ten and falls short of 162 one year in ten. On average 117 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 13 days longer, to about May 4, and return around October 12. Severe cold of 16°F or below comes every winter, usually between December 1 and February 19.

July is the warmest month at Ogden Pioneer Ph, UT, averaging 92°F by day and 64°F at night; January is the coldest at 38°F and 22°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 89% of years and May still brings one in 21% of years.

Warmth for growing adds up to 3,438 growing degree days a year (base 50°F), more than at 80% of the 66 Utah stations. 31% of them (1,053) have built up by the end of June, and July adds the most, 880. Precipitation totals 21.7 inches a year, most in May (2.6") and least in July (0.6"); May to September bring 32% of it.

The nearest other station, Ogden Sugar Factory, UT, 2 miles west of Ogden, has a last frost 1 day later (April 22), a first frost 5 days earlier (October 18), a season 7 days shorter.

The first measurable snow (0.1 inch or more) in Ogden usually arrives around November 29, and the last of the season around March 3. Those are the middle dates across the winters of 1991–2020 at Ogden Pioneer Ph, UT, 2.3 miles away: half of years saw snow earlier, half later. Snow fell in 89% of those winters. The last 32°F night of spring typically comes 49 days after the last snow.

ZIP 84401 is 2 miles from Ogden Pioneer Ph, UT, which stands at 4,350 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 84401 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.