Frost Dates for 95451 — Kelseyville, California

Half of springs at Clearlake 4 SE, CA see their last 32°F night by April 10; only one in ten is past it by March 24, and one in ten still has one after April 30. Planting tender crops after April 18 leaves a 30% risk of a frost on them, after April 23 20%, and after April 30 10%. The 20 days between the even-odds date and the one-in-ten date is narrower than at 88% of the 220 California stations behind this site's ZIP pages.

In fall the first 32°F night comes by November 6 in half of years, as early as October 24 one year in ten, and holds off past November 20 one year in ten. A hard freeze of 28°F follows 15 days later, around November 21; in spring the one-in-ten date for 28°F is April 7, 23 days before the 32°F one. The freeze-free season lasts 209 days in a typical year, shorter than at 79% of the 219 California stations; it reaches 231 days one year in ten and falls short of 186 one year in ten. On average 72 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 April 30, and return around October 27. Nights of 24°F, cold enough to damage hardier plants, come in 96% of winters and 16°F in 16%.

July is the warmest month at Clearlake 4 SE, CA, averaging 91°F by day and 56°F at night; January is the coldest at 55°F and 33°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 76% of years.

Warmth for growing adds up to 3,335 growing degree days a year (base 50°F), fewer than at 76% of the 283 California stations. 30% of them (1,009) have built up by the end of June, and July adds the most, 733. Precipitation totals 30.0 inches a year, most in January (6.2") and least in July (0.0"); May to September bring 6% of it.

The nearest other station, Cloverdale, CA, 16 miles southwest of Kelseyville and 949 feet lower, has a last frost 44 days earlier (February 25), a first frost 27 days later (December 3), a season 70 days longer.

Measurable snow is rare here: only 5 of 18 winters from 1991 to 2020 recorded 0.1 inch or more at Clearlake 4 SE, CA, 11.8 miles away, so there is no typical first-snow date to plan around.

ZIP 95451 is 12 miles from Clearlake 4 SE, CA, which stands at 1,349 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 6 other ZIP codes share the station; its figures are presented in full for 95422 (Clearlake). The 2023 USDA Plant Hardiness Zone Map lists ZIP 95451 in zone 9b, the band where the coldest night of the year averaged 25 to 30°F (-3.9 to -1.1°C) over 1991–2020; a zone describes winter lows, not frost dates.