Frost Dates for 85542 — Peridot, Arizona

Half of springs at San Carlos Reservoir, AZ see their last 32°F night by March 13; only one in ten is past it by February 17, and one in ten still has one after April 6. Planting tender crops after March 24 leaves a 30% risk of a frost on them, after March 30 20%, and after April 6 10%. The 24 days between the even-odds date and the one-in-ten date is wider than at 58% of the 98 Arizona 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 13, 24 days before the 32°F one. The freeze-free season lasts 247 days in a typical year, longer than at 55% of the 98 Arizona stations; it reaches 276 days one year in ten and falls short of 219 one year in ten. On average 42 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 19 days longer, to about April 1, and return around November 9. Nights of 24°F, cold enough to damage hardier plants, come in 93% of winters and 16°F in 13%.

July is the warmest month at San Carlos Reservoir, AZ, averaging 99°F by day and 71°F at night; December is the coldest at 59°F and 31°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 71% of years and April still brings one in 17% of years.

Warmth for growing adds up to 5,890 growing degree days a year (base 50°F), more than at 51% of the 102 Arizona stations. 38% of them (2,254) have built up by the end of June, and July adds the most, 1,076. Precipitation totals 13.5 inches a year, most in January (1.9") and least in June (0.1"); May to September bring 38% of it.

The nearest other station, Globe #3, AZ, 18 miles northwest of Peridot and 1,128 feet higher, has a last frost 2 days earlier (March 11), a first frost 2 days later (November 21), a season 6 days longer.

Measurable snow is rare here: only 0 of 15 winters from 1991 to 2020 recorded 0.1 inch or more at San Carlos Reservoir, AZ, 5.6 miles away, so there is no typical first-snow date to plan around.

ZIP 85542 is 6 miles from San Carlos Reservoir, AZ, which stands at 2,532 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 85542 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.