Frost Dates for 95005 — Ben Lomond, California

Half of springs at Ben Lomond #4, CA see their last 32°F night by March 25; only one in ten is past it by February 17, and one in ten still has one after April 21. Planting tender crops after April 4 leaves a 30% risk of a frost on them, after April 12 20%, and after April 21 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 11 in half of years, as early as October 18 one year in ten, and holds off past December 4 one year in ten. A hard freeze of 28°F follows 23 days later, around December 4; in spring the one-in-ten date for 28°F is March 9, 43 days before the 32°F one. The freeze-free season lasts 231 days in a typical year, shorter than at 74% of the 219 California stations; it reaches 272 days one year in ten and falls short of 197 one year in ten. On average 37 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 34 days longer, to about April 28, and return around October 21. Nights of 24°F, cold enough to damage hardier plants, come in 57% of winters.

August is the warmest month at Ben Lomond #4, CA, averaging 90°F by day and 51°F at night; December is the coldest at 64°F and 37°F. A freezing night is all but certain in December (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 81% of years and March still brings one in 68% of years and April still brings one in 37% of years.

Warmth for growing adds up to 3,982 growing degree days a year (base 50°F), fewer than at 60% of the 283 California stations. 38% of them (1,526) have built up by the end of June, and August adds the most, 628. Precipitation totals 49.5 inches a year, most in January (10.4") and least in July (0.0"); May to September bring 3% of it.

The nearest other station, Santa Cruz, CA, 8 miles southeast of Ben Lomond and 350 feet lower, has a last frost 55 days earlier (January 29), a first frost 32 days later (December 13), a season 92 days longer.

Measurable snow is rare here: only 2 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Ben Lomond #4, CA, 0.3 miles away, so there is no typical first-snow date to plan around.

ZIP 95005 is under a mile from Ben Lomond #4, CA, which stands at 420 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 95066 (Scotts Valley). The 2023 USDA Plant Hardiness Zone Map lists ZIP 95005 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.