Frost Dates for 95301 — Atwater, California

Half of springs at Merced, CA see their last 32°F night by March 3; only one in ten is past it by February 2, and one in ten still has one after April 10. Planting tender crops after March 19 leaves a 30% risk of a frost on them, after March 30 20%, and after April 10 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 24 in half of years, as early as November 5 one year in ten, and holds off past December 14 one year in ten. A hard freeze of 28°F follows 17 days later, around December 11; in spring the one-in-ten date for 28°F is March 11, 30 days before the 32°F one. The freeze-free season lasts 263 days in a typical year, shorter than at 60% of the 219 California stations; it reaches 303 days one year in ten and falls short of 226 one year in ten. On average 24 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 35 days longer, to about April 7, and return around November 8. Nights of 24°F, cold enough to damage hardier plants, come in 57% of winters and 16°F in 1%.

July is the warmest month at Merced, CA, averaging 95°F by day and 62°F at night; December is the coldest at 55°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 76% of years and March still brings one in 44% of years and April still brings one in 18% of years.

Warmth for growing adds up to 4,678 growing degree days a year (base 50°F), more than at 54% of the 283 California stations. 37% of them (1,725) have built up by the end of June, and July adds the most, 877. Precipitation totals 12.5 inches a year, most in January (2.7") and least in July (0.0"); May to September bring 6% of it.

The nearest other station, Merced Municipal Airport, CA, 7 miles southeast of Atwater, has a last frost 5 days earlier (February 26), a first frost 1 day later (November 25), a season 10 days longer.

Measurable snow is rare here: only 0 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Merced, CA, 6.5 miles away, so there is no typical first-snow date to plan around.

ZIP 95301 is 7 miles from Merced, CA, which stands at 154 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 95301 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.