Arizona Frost Dates & Growing Zones by City
Typical (50%) last spring frosts in the 3 Arizona cities with frost dates on this site fall between Jan 8 (Phoenix) and Feb 5 (Tucson). Typical frost-free seasons run from 307 days (Tucson) to 354 days (Phoenix).
By the 2023 USDA hardiness map, these cities are in zones 9a, 9b and 10a.
Dates come from the nearest NOAA station to each city that meets our quality rules, as the methodology explains.
| City | Last frost (50%) | First frost (50%) | Season (days, 50%) | Zone 2023 | Confidence | Planting calendar |
|---|---|---|---|---|---|---|
| Phoenix frost dates | Jan 8* | Dec 25* | 354 | 9b–10a | High | Phoenix planting calendar |
| Tucson frost dates | Feb 5* | Dec 9* | 307 | 9a–9b | High | Tucson planting calendar |
| Mesa frost dates | Feb 1* | Dec 10* | 312 | 9b–10a | Medium | Mesa planting calendar |
* Not every winter reaches 32°F here; the date describes the years that do (NOAA conditional probability).
Station match, data and rules: methodology. Long-term odds, not a forecast.