Frost Dates for 85705 — Tucson, Arizona

Half of springs at Tucson U Of A #1, AZ see their last 32°F night by February 11; only one in ten is past it by January 16, and one in ten still has one after March 7. Planting tender crops after February 22 leaves a 30% risk of a frost on them, after February 28 20%, and after March 7 10%. The 24 days between the even-odds date and the one-in-ten date is wider than at 58% 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 2 in half of years, as early as November 16 one year in ten, and holds off past December 20 one year in ten. A hard freeze of 28°F follows 13 days later, around December 15; in spring the one-in-ten date for 28°F is February 17, 18 days before the 32°F one. The freeze-free season lasts 293 days in a typical year, longer than at 68% of the 98 Arizona stations; it reaches 326 days one year in ten and falls short of 263 one year in ten. On average 21 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 6, and return around November 22. A 24°F night is unusual: 38% of winters had one.

July is the warmest month at Tucson U Of A #1, AZ, averaging 101°F by day and 75°F at night; December is the coldest at 67°F and 39°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 67% of years and March still brings one in 20% of years.

Warmth for growing adds up to 7,536 growing degree days a year (base 50°F), more than at 68% of the 102 Arizona stations. 41% of them (3,080) have built up by the end of June, and July adds the most, 1,186. Precipitation totals 10.7 inches a year, most in July (2.0") and least in May (0.2"); May to September bring 51% of it.

The nearest other station, Tucson Camp Ave Exp, AZ, 3 miles northeast of Tucson, has a last frost 9 days later (February 20), a first frost 5 days earlier (November 27), a season 13 days shorter.

Measurable snow is rare here: only 1 of 22 winters from 1991 to 2020 recorded 0.1 inch or more at Tucson U Of A #1, AZ, 1.2 miles away, so there is no typical first-snow date to plan around.

ZIP 85705 is 1 mile from Tucson U Of A #1, AZ, which stands at 2,315 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 85705 in zone 9b, the band where the coldest night of the year averaged 25 to 30°F (-3.9 to -1.1°C) over 1991–2020; a zone describes winter lows, not frost dates.