Frost Dates for 86507 — Lukachukai, Arizona

Half of springs at Lukachukai, AZ see their last 32°F night by May 3; only one in ten is past it by April 21, and one in ten still has one after May 22. Planting tender crops after May 10 leaves a 30% risk of a frost on them, after May 14 20%, and after May 22 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 17 in half of years, as early as October 2 one year in ten, and holds off past October 30 one year in ten. A hard freeze of 28°F follows 10 days later, around October 27; in spring the one-in-ten date for 28°F is May 9, 13 days before the 32°F one. The freeze-free season lasts 163 days in a typical year, shorter than at 82% of the 98 Arizona stations; it reaches 185 days one year in ten and falls short of 143 one year in ten. On average 146 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 13 days longer, to about May 16, and return around October 8. Severe cold of 16°F or below comes every winter, usually between November 25 and February 27.

July is the warmest month at Lukachukai, AZ, averaging 88°F by day and 59°F at night; January is the coldest at 39°F and 18°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 57% of years.

Warmth for growing adds up to 2,881 growing degree days a year (base 50°F), fewer than at 86% of the 102 Arizona stations. 31% of them (880) have built up by the end of June, and July adds the most, 717.

The nearest other station, Canyon De Chelly, AZ, 23 miles southwest of Lukachukai and 910 feet lower, has a last frost 3 days later (May 6), a first frost 9 days earlier (October 8), a season 10 days shorter.

The first measurable snow (0.1 inch or more) in Lukachukai usually arrives around December 6, and the last of the season around February 28. Those are the middle dates across the winters of 1991–2020 at Canyon De Chelly, AZ, 23 miles away: half of years saw snow earlier, half later. Snow fell in 90% of those winters. The last 32°F night of spring typically comes 64 days after the last snow.

ZIP 86507 is 4 miles from Lukachukai, AZ, which stands at 6,520 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 86556 (Tsaile). The 2023 USDA Plant Hardiness Zone Map lists ZIP 86507 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.