Frost Dates for 86320 — Ash Fork, Arizona

Half of springs at Seligman, AZ see their last 32°F night by May 10; only one in ten is past it by April 26, and one in ten still has one after May 29. Planting tender crops after May 17 leaves a 30% risk of a frost on them, after May 22 20%, and after May 29 10%. The 19 days between the even-odds date and the one-in-ten date is narrower than at 61% of the 98 Arizona stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 15 in half of years, as early as October 1 one year in ten, and holds off past October 30 one year in ten. A hard freeze of 28°F follows 11 days later, around October 26; in spring the one-in-ten date for 28°F is May 13, 16 days before the 32°F one. The freeze-free season lasts 154 days in a typical year, shorter than at 86% of the 98 Arizona stations; it reaches 176 days one year in ten and falls short of 132 one year in ten. On average 148 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 18 days longer, to about May 28, and return around October 5. Severe cold of 16°F or below comes every winter, usually between November 30 and February 18.

July is the warmest month at Seligman, AZ, averaging 93°F by day and 57°F at night; December is the coldest at 53°F and 23°F. A freezing night is all but certain in every month from October 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 75% of years.

Warmth for growing adds up to 3,326 growing degree days a year (base 50°F), fewer than at 81% of the 102 Arizona stations. 31% of them (1,044) have built up by the end of June, and July adds the most, 778. Precipitation totals 12.0 inches a year, most in August (2.1") and least in June (0.2"); May to September bring 47% of it.

The nearest other station, Williams, AZ, 21 miles east of Ash Fork and 1,659 feet higher, has a last frost 12 days later (May 22), a first frost 10 days earlier (October 5), a season 19 days shorter.

The first measurable snow (0.1 inch or more) in Ash Fork usually arrives around December 9, and the last of the season around February 26. Those are the middle dates across the winters of 1991–2020 at Seligman, AZ, 20.7 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 73 days after the last snow.

ZIP 86320 is 21 miles from Seligman, AZ, which stands at 5,250 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 86320 in zone 7a, the band where the coldest night of the year averaged 0 to 5°F (-17.8 to -15.0°C) over 1991–2020; a zone describes winter lows, not frost dates.