Frost Dates for 85539 — Miami, Arizona

Half of springs at Miami, AZ see their last 32°F night by February 24; only one in ten is past it by January 30, and one in ten still has one after March 18. Planting tender crops after March 5 leaves a 30% risk of a frost on them, after March 9 20%, and after March 18 10%. The 22 days between the even-odds date and the one-in-ten date is wider than at 54% 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 December 1 in half of years, as early as November 15 one year in ten, and holds off past December 15 one year in ten. A hard freeze of 28°F follows 12 days later, around December 13; in spring the one-in-ten date for 28°F is February 28, 18 days before the 32°F one. The freeze-free season lasts 279 days in a typical year, longer than at 63% of the 98 Arizona stations; it reaches 308 days one year in ten and falls short of 247 one year in ten. On average 25 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 23 days longer, to about March 19, and return around November 19. Nights of 24°F, cold enough to damage hardier plants, come in 56% of winters and 16°F in 1%.

July is the warmest month at Miami, AZ, averaging 100°F by day and 72°F at night; December is the coldest at 61°F and 35°F. A freezing night is all but certain in every month from December to January (a 90% chance or more). From April to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 79% of years and March still brings one in 39% of years.

Warmth for growing adds up to 6,464 growing degree days a year (base 50°F), more than at 56% of the 102 Arizona stations. 39% of them (2,489) have built up by the end of June, and July adds the most, 1,110. Precipitation totals 17.2 inches a year, most in August (2.6") and least in May (0.3"); May to September bring 38% of it.

The nearest other station, Globe #3, AZ, 6 miles east of Miami, has a last frost 15 days later (March 11), a first frost 10 days earlier (November 21), a season 26 days shorter.

Measurable snow is rare here: only 0 of 19 winters from 1991 to 2020 recorded 0.1 inch or more at Miami, AZ, 2.2 miles away, so there is no typical first-snow date to plan around.

ZIP 85539 is 2 miles from Miami, AZ, which stands at 3,560 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 85539 in zone 8a, the band where the coldest night of the year averaged 10 to 15°F (-12.2 to -9.4°C) over 1991–2020; a zone describes winter lows, not frost dates.