Frost Dates for 86301 — Prescott, Arizona

Half of springs at Prescott, AZ see their last 32°F night by April 30; only one in ten is past it by April 14, and one in ten still has one after May 15. Planting tender crops after May 6 leaves a 30% risk of a frost on them, after May 10 20%, and after May 15 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 91% of the 98 Arizona stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 20 in half of years, as early as October 7 one year in ten, and holds off past November 4 one year in ten. A hard freeze of 28°F follows 11 days later, around October 31; in spring the one-in-ten date for 28°F is May 2, 13 days before the 32°F one. The freeze-free season lasts 172 days in a typical year, shorter than at 80% of the 98 Arizona stations; it reaches 193 days one year in ten and falls short of 153 one year in ten. On average 128 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 12 days longer, to about May 12, and return around October 10. Severe cold of 16°F or below comes every winter, usually between December 5 and February 10.

July is the warmest month at Prescott, AZ, averaging 90°F by day and 61°F at night; December is the coldest at 52°F and 24°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 48% of years.

Warmth for growing adds up to 3,424 growing degree days a year (base 50°F), fewer than at 78% of the 102 Arizona stations. 33% of them (1,127) have built up by the end of June, and July adds the most, 784. Precipitation totals 16.6 inches a year, most in August (2.8") and least in June (0.2"); May to September bring 47% of it.

The nearest other station, Prescott Love Field, AZ, 5 miles north of Prescott and 163 feet lower, has a last frost 10 days earlier (April 20), a first frost 7 days later (October 27), a season 16 days longer.

The first measurable snow (0.1 inch or more) in Prescott usually arrives around December 20, and the last of the season around March 9. Those are the middle dates across the winters of 1991–2020 at Prescott, AZ, 1.6 miles away: half of years saw snow earlier, half later. Snow fell in 97% of those winters. The last 32°F night of spring typically comes 52 days after the last snow.

ZIP 86301 is 2 miles from Prescott, AZ, which stands at 5,205 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 86301 in zone 7b, the band where the coldest night of the year averaged 5 to 10°F (-15.0 to -12.2°C) over 1991–2020; a zone describes winter lows, not frost dates.