Frost Dates for 95713 — Colfax, California

Half of springs at Colfax, CA see their last 32°F night by April 3; only one in ten is past it by February 28, and one in ten still has one after April 29. Planting tender crops after April 13 leaves a 30% risk of a frost on them, after April 19 20%, and after April 29 10%. The 26 days between the even-odds date and the one-in-ten date is narrower than at 67% 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 24 in half of years, as early as November 2 one year in ten, and holds off past December 11 one year in ten. A hard freeze of 28°F follows 19 days later, around December 13; in spring the one-in-ten date for 28°F is April 6, 23 days before the 32°F one. The freeze-free season lasts 233 days in a typical year, shorter than at 73% of the 219 California stations; it reaches 270 days one year in ten and falls short of 198 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 20 days longer, to about April 23, and return around November 7. Nights of 24°F, cold enough to damage hardier plants, come in 51% of winters.

July is the warmest month at Colfax, CA, averaging 92°F by day and 63°F at night; December is the coldest at 54°F and 36°F. A freezing night is all but certain in every month from December to January (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 87% of years and March still brings one in 75% of years and April still brings one in 51% of years.

Warmth for growing adds up to 4,102 growing degree days a year (base 50°F), fewer than at 57% of the 283 California stations. 32% of them (1,296) have built up by the end of June, and July adds the most, 846. Precipitation totals 45.9 inches a year, most in December (8.5") and least in July (0.0"); May to September bring 8% of it.

The nearest other station, Grass Valley #2, CA, 11 miles northwest of Colfax, has a last frost 7 days later (April 10), a first frost 11 days earlier (November 13), a season 18 days shorter.

Measurable snow is rare here: only 11 of 25 winters from 1991 to 2020 recorded 0.1 inch or more at Foresthill Rs, CA, 7.4 miles away, so there is no typical first-snow date to plan around.

ZIP 95713 is under a mile from Colfax, CA, which stands at 2,380 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 95713 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.