Frost Dates for 95570 — Trinidad, California

Half of springs at Arcata Eureka Airport, CA see their last 32°F night by March 8; only one in ten is past it by January 13, and one in ten still has one after April 15. Planting tender crops after March 28 leaves a 30% risk of a frost on them, after April 5 20%, and after April 15 10%. The 38 days between the even-odds date and the one-in-ten date is wider than at 81% 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 30 in half of years, as early as November 1 one year in ten, and holds off past January 4 one year in ten. A hard freeze of 28°F follows 24 days later, around December 24; in spring the one-in-ten date for 28°F is February 26, 48 days before the 32°F one. The freeze-free season lasts 262 days in a typical year, shorter than at 61% of the 219 California stations; it reaches 315 days one year in ten and falls short of 216 one year in ten. On average 19 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 47 days longer, to about April 24, and return around November 1. A 24°F night is unusual: 14% of winters had one.

August is the warmest month at Arcata Eureka Airport, CA, averaging 65°F by day and 51°F at night; December is the coldest at 56°F and 40°F. From May to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 60% of years and March still brings one in 41% of years and April still brings one in 24% of years.

Warmth for growing adds up to 1,374 growing degree days a year (base 50°F), fewer than at 98% of the 283 California stations. 32% of them (442) have built up by the end of June, and August adds the most, 245. Precipitation totals 46.3 inches a year, most in December (9.0") and least in July (0.2"); May to September bring 10% of it.

The nearest other station, Eureka WFO Woodley Island, CA, 19 miles south of Trinidad and 180 feet lower, has a last frost 14 days earlier (February 22), a first frost 7 days later (December 7), a season 31 days longer.

Measurable snow is rare here: only 4 of 30 winters from 1991 to 2020 recorded 0.1 inch or more at Eureka WFO Woodley Island, CA, 18.9 miles away, so there is no typical first-snow date to plan around.

ZIP 95570 is 7 miles from Arcata Eureka Airport, CA, which stands at 200 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 95519 (Mckinleyville). The 2023 USDA Plant Hardiness Zone Map lists ZIP 95570 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.