Arizona frost dates by city
| City | Last frost (50%) | Safer date (10%) | First frost (50%) | Season |
|---|---|---|---|---|
| Flagstaff | Jun 4 | Jun 19 | Sep 28 | 115 days |
| Phoenix | Frost uncommon | |||
| Tucson | Feb 5 | Mar 2 | Dec 9 | 307 days |
Each city uses its nearest major NOAA weather station, usually the airport. Valleys, hilltops and rural spots can differ from it by one to three weeks. How to read these dates.