Frost dates in Arizona
Across Arizona, the typical last spring frost is around Feb 20 and the first fall frost around Nov 27. Your own dates depend on where you are in the state; find your county below.
Most of the state's last spring frosts fall between Jan 7 and May 15, and its first fall frosts between Oct 6 and Dec 24.
These are the dates with a 50% chance of a 32°F frost on or after (spring) or on or before (fall), so plan tender crops a week or two after the spring date and keep row cover handy. For dates at your exact ZIP code, use the zone and frost date lookup; for what to plant when, see the planting guide by frost date.
Hardiness zones in Arizona: zone 5b, zone 6a, zone 6b, zone 7a, zone 7b, zone 8a, zone 8b, zone 9a, zone 9b, zone 10a
Frost dates by county in Arizona
| County | Last spring frost | First fall frost | Growing season |
|---|---|---|---|
| Apache | May 15 | Oct 10 | About 148 days |
| Cochise | Apr 6 | Nov 9 | About 217 days |
| Coconino | May 9 | Oct 19 | About 163 days |
| Gila | Mar 13 | Nov 20 | About 252 days |
| Graham | Mar 25 | Nov 9 | About 229 days |
| Greenlee | Apr 24 | Nov 23 | About 213 days |
| La Paz | Feb 18 | Dec 6 | About 291 days |
| Maricopa | Jan 20 | Dec 15 | About 329 days |
| Mohave | Feb 18 | Dec 2 | About 287 days |
| Navajo | May 11 | Oct 13 | About 155 days |
| Pima | Feb 8 | Dec 9 | About 304 days |
| Pinal | Feb 6 | Dec 6 | About 303 days |
| Santa Cruz | Apr 5 | Nov 10 | About 219 days |
| Yavapai | Apr 16 | Nov 10 | About 208 days |
| Yuma | Jan 11 | Dec 21 | About 344 days |
Source: NOAA NCEI U.S. Climate Normals 1991–2020, 50% probability of 32°F, from the weather station nearest each ZIP code; each county shows the middle value across its ZIP codes. Hills, valleys and cities can run a week or more earlier or later.