Frost Dates for 95428 — Covelo, California

Half of springs at Covelo, CA see their last 32°F night by April 23; only one in ten is past it by April 4, and one in ten still has one after May 11. Planting tender crops after April 29 leaves a 30% risk of a frost on them, after May 3 20%, and after May 11 10%. The 18 days between the even-odds date and the one-in-ten date is narrower than at 93% of the 220 California stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 19 in half of years, as early as October 2 one year in ten, and holds off past November 8 one year in ten. A hard freeze of 28°F follows 15 days later, around November 3; in spring the one-in-ten date for 28°F is April 18, 23 days before the 32°F one. The freeze-free season lasts 179 days in a typical year, shorter than at 86% of the 219 California stations; it reaches 204 days one year in ten and falls short of 153 one year in ten. On average 77 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 13, and return around October 4. Nights of 24°F, cold enough to damage hardier plants, come in 99% of winters and 16°F in 26%.

July is the warmest month at Covelo, CA, averaging 92°F by day and 53°F at night; December is the coldest at 50°F and 32°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 25% of years.

Warmth for growing adds up to 3,078 growing degree days a year (base 50°F), fewer than at 83% of the 283 California stations. 31% of them (957) have built up by the end of June, and July adds the most, 699. Precipitation totals 40.5 inches a year, most in December (8.8") and least in July (0.0"); May to September bring 7% of it.

The nearest other station, Willits 1 NE, CA, 29 miles south of Covelo, has a last frost 12 days later (May 5), a first frost 10 days earlier (October 9), a season 22 days shorter.

The first measurable snow (0.1 inch or more) in Covelo usually arrives around December 26, and the last of the season around March 4. Those are the middle dates across the winters of 1991–2020 at Covelo, CA, 1 miles away: half of years saw snow earlier, half later. Snow fell in 50% of those winters. The last 32°F night of spring typically comes 50 days after the last snow.

ZIP 95428 is 1 mile from Covelo, CA, which stands at 1,413 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 95428 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.