Frost Dates for 85390 — Wickenburg, Arizona

Half of springs at Wickenburg, AZ see their last 32°F night by March 7; only one in ten is past it by February 14, and one in ten still has one after April 8. Planting tender crops after March 18 leaves a 30% risk of a frost on them, after March 30 20%, and after April 8 10%. The 32 days between the even-odds date and the one-in-ten date is wider than at 87% 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 20 in half of years, as early as November 4 one year in ten, and holds off past December 5 one year in ten. A hard freeze of 28°F follows 12 days later, around December 2; in spring the one-in-ten date for 28°F is March 6, 33 days before the 32°F one. The freeze-free season lasts 254 days in a typical year, longer than at 58% of the 98 Arizona stations; it reaches 282 days one year in ten and falls short of 223 one year in ten. On average 47 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 27 days longer, to about April 3, and return around November 9. Nights of 24°F, cold enough to damage hardier plants, come in 91% of winters and 16°F in 4%.

July is the warmest month at Wickenburg, AZ, averaging 104°F by day and 73°F at night; December is the coldest at 64°F and 33°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 58% of years and April still brings one in 18% of years.

Warmth for growing adds up to 6,532 growing degree days a year (base 50°F), more than at 57% of the 102 Arizona stations. 38% of them (2,454) have built up by the end of June, and July adds the most, 1,189. Precipitation totals 11.0 inches a year, most in August (2.0") and least in June (0.1"); May to September bring 41% of it.

The nearest other station, Wittmann 1SE, AZ, 19 miles southeast of Wickenburg and 412 feet lower, has a last frost 30 days earlier (February 5), a first frost 21 days later (December 11), a season 52 days longer.

Measurable snow is rare here: only 1 of 22 winters from 1991 to 2020 recorded 0.1 inch or more at Wickenburg, AZ, 2.1 miles away, so there is no typical first-snow date to plan around.

ZIP 85390 is 2 miles from Wickenburg, AZ, which stands at 2,095 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 85390 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.