Frost dates for Tombstone, AZ
At Tombstone, the median last spring frost (32°F) is Mar 4 and the median first fall frost is Nov 29, for a typical growing season of 264 days. For a 90% chance that the last frost has passed, wait until Mar 31. Nearby ZIP codes are in USDA hardiness zone 8b.
- Mar 4Last spring frost (median)50% chance of 32°F after this date
- Mar 31Safer planting date10% chance of 32°F after this date
- Nov 29First fall frost (median)50% chance of 32°F by this date
- 264 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 36°F | Mar 5 | Mar 29 | Apr 18 |
| 32°F | Feb 3 | Mar 4 | Mar 31 |
| 28°F | Jan 5 | Feb 8 | Mar 10 |
| 24°F | Dec 14 | Jan 15 | Feb 18 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 36°F | Oct 31 | Nov 17 | Dec 3 |
| 32°F | Nov 12 | Nov 29 | Dec 17 |
| 28°F | Nov 23 | Dec 12 | Jan 10 |
| 24°F | Dec 3 | Dec 28 | Jan 30 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 206 days | 231 days | 257 days |
| 32°F | 235 days | 264 days | 296 days |
| 28°F | 269 days | 305 days | 342 days |
| 24°F | 309 days | 347 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 98% |
| 24°F | 75% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 85638 | 8b | 15 to 20°F | 5 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USC00028619, at 31.7119, -110.0686, elevation 1420 m (4,659 ft).
- Data quality: Standard (24+ years of data), 29 years of freeze data.
- Average days per year at or below 32°F: 29.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Benson 6se (25 km)
- Sierra Vista (28 km)
- Kartchner Caverns (30 km)
- Bisbee 1wnw (32 km)
- Pearce - Sunsites (33 km)
- Fort Huachuca Pioneer Airfield (36 km)
- Mc Neal (40 km)
- Elgin 5 S (44 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.