Frost Dates for 86503 — Chinle, Arizona

Half of springs at Canyon De Chelly, AZ see their last 32°F night by May 6; only one in ten is past it by April 22, and one in ten still has one after May 31. Planting tender crops after May 15 leaves a 30% risk of a frost on them, after May 22 20%, and after May 31 10%. The 25 days between the even-odds date and the one-in-ten date is wider than at 63% 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 October 8 in half of years, as early as September 26 one year in ten, and holds off past October 23 one year in ten. A hard freeze of 28°F follows 10 days later, around October 18; in spring the one-in-ten date for 28°F is May 12, 19 days before the 32°F one. The freeze-free season lasts 153 days in a typical year, shorter than at 87% of the 98 Arizona stations; it reaches 173 days one year in ten and falls short of 130 one year in ten. On average 139 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 15 days longer, to about May 21, and return around October 1. Severe cold of 16°F or below comes every winter, usually between November 19 and March 3.

July is the warmest month at Canyon De Chelly, AZ, averaging 93°F by day and 60°F at night; January is the coldest at 44°F and 19°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 63% of years.

Warmth for growing adds up to 3,391 growing degree days a year (base 50°F), fewer than at 80% of the 102 Arizona stations. 34% of them (1,152) have built up by the end of June, and July adds the most, 823. Precipitation totals 8.9 inches a year, most in August (1.3") and least in June (0.3"); May to September bring 46% of it.

The nearest other station, Lukachukai, AZ, 28 miles northeast of Chinle and 910 feet higher, has a last frost 3 days earlier (May 3), a first frost 9 days later (October 17), a season 10 days longer.

The first measurable snow (0.1 inch or more) in Chinle 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, 4.6 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 67 days after the last snow.

ZIP 86503 is 5 miles from Canyon De Chelly, AZ, which stands at 5,610 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 86503 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.