Frost Dates for 85037 — Phoenix, Arizona

In the 77% of winters that bring a 32°F night, half of springs at Litchfield Park, AZ see their last 32°F night by January 7; only one in ten is past it by December 17, and one in ten still has one after February 5. Counting the winters with no freeze at all, the risk of a 32°F night after February 5 is under 8% and after January 7 38%. The 29 days between the even-odds date and the one-in-ten date is wider than at 79% 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 24 in half of years, as early as December 6 one year in ten, and holds off past January 16 one year in ten. A hard freeze of 28°F is less common: it came in 20% of winters. The freeze-free season lasts 351 days in a typical year, longer than at 94% of the 98 Arizona stations; it reaches 365 days one year in ten and falls short of 320 one year in ten. On average 7 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 24 days longer, to about January 31, and return around December 9. A 24°F night is unusual: 2% of winters had one.

July is the warmest month at Litchfield Park, AZ, averaging 107°F by day and 81°F at night; December is the coldest at 65°F and 42°F. From March to November the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 11% of years.

Warmth for growing adds up to 8,590 growing degree days a year (base 50°F), more than at 88% of the 102 Arizona stations. 41% of them (3,563) have built up by the end of June, and July adds the most, 1,359. Precipitation totals 8.4 inches a year, most in February (1.2") and least in June (0.0"); May to September bring 33% of it.

The nearest other station, Youngtown, AZ, 8 miles north of Phoenix, has a last frost 13 days later (January 20), a first frost 9 days earlier (December 15), a season 20 days shorter.

Measurable snow is rare here: only 5 of 19 winters from 1991 to 2020 recorded 0.1 inch or more at Tolleson 1 E, AZ, 2.9 miles away, so there is no typical first-snow date to plan around.

ZIP 85037 is 6 miles from Litchfield Park, AZ, which stands at 1,040 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 10 other ZIP codes share the station; its figures are presented in full for 85326 (Buckeye). The 2023 USDA Plant Hardiness Zone Map lists ZIP 85037 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.