Frost dates in Phoenix, Arizona
NOAA 1991–2020 normals for a 32 °F freeze. Low spots and the edge of town run colder than downtown.
Short answer
The average last spring frost in Phoenix is January 8, and the average first fall frost is December 25, from NOAA's Phoenix Deer Valley Muni Airport station, 8 miles from the middle of Phoenix. 1 year in 10 the last frost comes after February 12, and the first one by December 5. That leaves about 351 frost-free days. Phoenix is in USDA planting zone 9b.
Weather stations around Phoenix
The first row is the date most people in Phoenix go by. The others show how far the dates move across the area.
| Station | Last spring frost | First fall frost | Frost-free |
|---|---|---|---|
| Phoenix Deer Valley Muni Airport 8 mi away, 1,455 ft | January 8 1 in 10 after February 12 | December 25 1 in 10 by December 5 | 351 days |
| Scottsdale Muni Airport 11 mi away, 1,473 ft | January 6 1 in 10 after February 7 | December 26 1 in 10 by December 4 | 354 days |
| Phoenix Sky Harbor Intl Airport 11 mi away, 1,107 ft | January 5 1 in 10 after January 22 | January 3 1 in 10 by December 18 | 363 days |
| Youngtown 12 mi away, 1,135 ft | January 20 1 in 10 after February 18 | December 15 1 in 10 by November 28 | 329 days |
| South Phoenix 13 mi away, 1,155 ft | January 21 1 in 10 after February 20 | December 16 1 in 10 by November 29 | 329 days |
Distances are from the middle of Phoenix as the Census Bureau maps it. The average date is NOAA's 50% date: half of years have a later last frost, or an earlier first one. Plan by the 1-in-10 date if a freeze would cost you plants. The planting zone is the USDA 2023 zone for ZIP code 85021, at the middle of the city.
Your exact ZIP code
Phoenix covers a lot of ground. For the station nearest your own street, and its planting zone, type your ZIP code.
How these dates work
Frost dates come from NOAA's 1991 to 2020 Climate Normals, which work out from each weather station's daily lows how likely the last spring freeze and the first fall freeze (32 °F) are by each date. We use the station nearest the middle of your ZIP code and show its height and distance, since a station on a hill or by a lake can differ from your yard.
The average date is the 50% date: half of years have a freeze after the spring date or before the fall one. The 1-in-10 dates are NOAA's 10% dates, the ones to plan by if a late freeze would cost you plants. Within one yard, cold air pools in low spots while walls and paving hold heat, so some corners freeze before others.
More frost dates
All of Arizona, station by station.
Other Arizona cities: Tucson · Mesa · Gilbert · Chandler · Glendale · Scottsdale · Peoria · Tempe · Surprise
Where the numbers come from
- USDA Plant Hardiness Zone Map, 2023. Agricultural Research Service, U.S. Department of Agriculture
- PRISM Climate Group, Oregon State University (zone data)
- NOAA NCEI, U.S. Climate Normals 1991–2020, annual/seasonal
- NOAA, Normals calculation methodology (frost-freeze probability dates)
- US Census Bureau, 2025 ZCTA gazetteer (ZIP code centers)
- US Census Bureau, 2025 city population estimates and place gazetteer