Frost Dates for 91390 — Santa Clarita, California

Half of springs at Palmdale, CA see their last 32°F night by March 10; only one in ten is past it by February 12, and one in ten still has one after April 11. Planting tender crops after March 27 leaves a 30% risk of a frost on them, after April 2 20%, and after April 11 10%. The 32 days between the even-odds date and the one-in-ten date is wider than at 55% 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 19 in half of years, as early as November 3 one year in ten, and holds off past December 4 one year in ten. A hard freeze of 28°F follows 12 days later, around December 1; in spring the one-in-ten date for 28°F is March 17, 25 days before the 32°F one. The freeze-free season lasts 248 days in a typical year, shorter than at 68% of the 219 California stations; it reaches 282 days one year in ten and falls short of 216 one year in ten. On average 38 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 26 days longer, to about April 5, and return around November 7. Nights of 24°F, cold enough to damage hardier plants, come in 85% of winters and 16°F in 5%.

July is the warmest month at Palmdale, CA, averaging 98°F by day and 68°F at night; December is the coldest at 58°F and 34°F. A freezing night is all but certain in every month from December to February (a 90% chance or more). From May to October the chance of a 32°F night stays under 10% each month. In spring, March still brings one in 56% of years and April still brings one in 23% of years.

Warmth for growing adds up to 5,415 growing degree days a year (base 50°F), more than at 77% of the 283 California stations. 36% of them (1,965) have built up by the end of June, and July adds the most, 1,009. Precipitation totals 7.2 inches a year, most in February (1.8") and least in June (0.0"); May to September bring 6% of it.

The nearest other station, Palmdale Airport, CA, 16 miles northeast of Santa Clarita, has a last frost 8 days later (March 18), a first frost 4 days earlier (November 15), a season 7 days shorter.

Measurable snow is rare here: only 0 of 18 winters from 1991 to 2020 recorded 0.1 inch or more at Acton Escondido Fc261, CA, 1.7 miles away, so there is no typical first-snow date to plan around.

ZIP 91390 is 14 miles from Palmdale, CA, which stands at 2,612 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 4 other ZIP codes share the station; its figures are presented in full for 93550 (Palmdale). The 2023 USDA Plant Hardiness Zone Map lists ZIP 91390 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.