Frost Dates for 93451 — San Miguel, California

Half of springs at Paso Robles Municipal Airport, CA see their last 32°F night by April 4; only one in ten is past it by March 2, and one in ten still has one after April 27. Planting tender crops after April 14 leaves a 30% risk of a frost on them, after April 21 20%, and after April 27 10%. The 23 days between the even-odds date and the one-in-ten date is narrower than at 78% 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 5 in half of years, as early as October 17 one year in ten, and holds off past November 24 one year in ten. A hard freeze of 28°F follows 16 days later, around November 21; in spring the one-in-ten date for 28°F is March 31, 27 days before the 32°F one. The freeze-free season lasts 213 days in a typical year, shorter than at 77% of the 219 California stations; it reaches 251 days one year in ten and falls short of 183 one year in ten. On average 45 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 25 days longer, to about April 29, and return around October 21. Nights of 24°F, cold enough to damage hardier plants, come in 86% of winters and 16°F in 11%.

August is the warmest month at Paso Robles Municipal Airport, CA, averaging 94°F by day and 53°F at night; December is the coldest at 60°F and 33°F. A freezing night is all but certain in every month from November to January (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 86% of years and March still brings one in 76% of years and April still brings one in 56% of years.

Warmth for growing adds up to 4,015 growing degree days a year (base 50°F), fewer than at 59% of the 283 California stations. 36% of them (1,437) have built up by the end of June, and August adds the most, 732. Precipitation totals 12.2 inches a year, most in January (2.7") and least in June (0.0"); May to September bring 4% of it.

The nearest other station, Paso Robles, CA, 13 miles south of San Miguel, has a last frost 20 days earlier (March 15), a first frost 5 days later (November 10), a season 25 days longer.

Measurable snow is rare here: only 0 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Paso Robles, CA, 13.4 miles away, so there is no typical first-snow date to plan around.

ZIP 93451 is 10 miles from Paso Robles Municipal Airport, CA, which stands at 810 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 93451 in zone 8b, the band where the coldest night of the year averaged 15 to 20°F (-9.4 to -6.7°C) over 1991–2020; a zone describes winter lows, not frost dates.