Frost Dates for 86505 — Ganado, Arizona

Half of springs at Ganado, AZ see their last 32°F night by May 15; only one in ten is past it by April 30, and one in ten still has one after June 1. Planting tender crops after May 23 leaves a 30% risk of a frost on them, after May 27 20%, and after June 1 10%. The 17 days between the even-odds date and the one-in-ten date is narrower than at 80% of the 98 Arizona stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 10 in half of years, as early as September 28 one year in ten, and holds off past October 24 one year in ten. A hard freeze of 28°F follows 9 days later, around October 19; in spring the one-in-ten date for 28°F is May 21, 11 days before the 32°F one. The freeze-free season lasts 147 days in a typical year, shorter than at 90% of the 98 Arizona stations; it reaches 167 days one year in ten and falls short of 124 one year in ten. On average 174 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 14 days longer, to about May 29, and return around October 1. Severe cold of 16°F or below comes every winter, usually between November 16 and March 10.

July is the warmest month at Ganado, AZ, averaging 89°F by day and 56°F at night; January is the coldest at 44°F and 18°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 87% of years and June still brings one in 10% of years.

Warmth for growing adds up to 2,719 growing degree days a year (base 50°F), fewer than at 91% of the 102 Arizona stations. 29% of them (801) have built up by the end of June, and July adds the most, 700.

The nearest other station, Keams Canyon, AZ, 32 miles west of Ganado, has a last frost 1 day later (May 16), the same first-frost date.

The first measurable snow (0.1 inch or more) in Ganado usually arrives around December 9, and the last of the season around February 1. Those are the middle dates across the winters of 1991–2020 at Ganado, AZ, 6.3 miles away: half of years saw snow earlier, half later. Snow fell in 68% of those winters. The last 32°F night of spring typically comes 103 days after the last snow.

ZIP 86505 is 6 miles from Ganado, AZ, which stands at 6,340 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 86505 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.