Frost Dates for 95482 — Ukiah, California

Half of springs at Ukiah, CA see their last 32°F night by March 19; only one in ten is past it by February 13, and one in ten still has one after April 15. Planting tender crops after April 2 leaves a 30% risk of a frost on them, after April 7 20%, and after April 15 10%. The 27 days between the even-odds date and the one-in-ten date is narrower than at 65% of the 220 California 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 November 20 in half of years, as early as November 2 one year in ten, and holds off past December 9 one year in ten. A hard freeze of 28°F follows 15 days later, around December 5; in spring the one-in-ten date for 28°F is March 13, 33 days before the 32°F one. The freeze-free season lasts 245 days in a typical year, shorter than at 68% of the 219 California stations; it reaches 285 days one year in ten and falls short of 212 one year in ten. On average 34 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 29 days longer, to about April 17, and return around November 2. Nights of 24°F, cold enough to damage hardier plants, come in 51% of winters.

July is the warmest month at Ukiah, CA, averaging 91°F by day and 56°F at night; December is the coldest at 56°F and 36°F. A freezing night is all but certain in December (a 90% chance or more). From May to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 78% of years and March still brings one in 66% of years and April still brings one in 31% of years.

Warmth for growing adds up to 3,702 growing degree days a year (base 50°F), fewer than at 67% of the 283 California stations. 34% of them (1,259) have built up by the end of June, and July adds the most, 724. Precipitation totals 39.0 inches a year, most in December (8.0") and least in July (0.0"); May to September bring 6% of it.

The nearest other station, Ukiah Municipal Airport, CA, 2 miles south of Ukiah, has a last frost 14 days earlier (March 5), a first frost 1 day later (November 21), a season 14 days longer.

Measurable snow is rare here: only 1 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Ukiah, CA, 0.8 miles away, so there is no typical first-snow date to plan around.

ZIP 95482 is under a mile from Ukiah, CA, which stands at 636 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 95482 in zone 9a, the band where the coldest night of the year averaged 20 to 25°F (-6.7 to -3.9°C) over 1991–2020; a zone describes winter lows, not frost dates.