Frost Dates for 86046 — Williams, Arizona

Half of springs at Williams, AZ see their last 32°F night by May 22; only one in ten is past it by May 6, and one in ten still has one after June 10. Planting tender crops after May 31 leaves a 30% risk of a frost on them, after June 4 20%, and after June 10 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 5 in half of years, as early as September 24 one year in ten, and holds off past October 18 one year in ten. A hard freeze of 28°F follows 10 days later, around October 15; in spring the one-in-ten date for 28°F is June 1, 9 days before the 32°F one. The freeze-free season lasts 135 days in a typical year, shorter than at 95% of the 98 Arizona stations; it reaches 157 days one year in ten and falls short of 112 one year in ten. On average 150 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 11 days longer, to about June 2, and return around September 30. Severe cold of 16°F or below comes every winter, usually between November 20 and March 17.

July is the warmest month at Williams, AZ, averaging 84°F by day and 54°F at night; December is the coldest at 47°F and 21°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 28% of years.

Warmth for growing adds up to 2,269 growing degree days a year (base 50°F), fewer than at 96% of the 102 Arizona stations. 31% of them (693) have built up by the end of June, and July adds the most, 584. Precipitation totals 21.7 inches a year, most in August (3.4") and least in June (0.4"); May to September bring 42% of it.

The nearest other station, Williams 35 NNW, AZ, 27 miles north of Williams and 919 feet lower, has a last frost 13 days earlier (May 9), a first frost 14 days later (October 19), a season 26 days longer.

The first measurable snow (0.1 inch or more) in Williams usually arrives around November 21, and the last of the season around April 2. Those are the middle dates across the winters of 1991–2020 at Williams, AZ, 9.8 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 50 days after the last snow.

ZIP 86046 is 10 miles from Williams, AZ, which stands at 6,909 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 86046 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.