Frost dates for Kitt Peak, AZ
At Kitt Peak, the median last spring frost (32°F) is Apr 26 and the median first fall frost is Nov 4, for a typical growing season of 195 days. For a 90% chance that the last frost has passed, wait until May 17. Nearby ZIP codes are in USDA hardiness zone 9a.
- Apr 26Last spring frost (median)50% chance of 32°F after this date
- May 17Safer planting date10% chance of 32°F after this date
- Nov 4First fall frost (median)50% chance of 32°F by this date
- 195 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 | Apr 18 | May 7 | May 29 |
| 32°F | Apr 1 | Apr 26 | May 17 |
| 28°F | Mar 8 | Apr 7 | May 5 |
| 24°F | Feb 10 | Mar 17 | Apr 23 |
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 10 | Oct 26 | Nov 13 |
| 32°F | Oct 18 | Nov 4 | Nov 24 |
| 28°F | Oct 27 | Nov 17 | Dec 8 |
| 24°F | Nov 9 | Dec 3 | Dec 25 |
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 | 146 days | 171 days | 198 days |
| 32°F | 165 days | 195 days | 225 days |
| 28°F | 190 days | 223 days | 257 days |
| 24°F | 223 days | 258 days | 300 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 85639 | 9a | 20 to 25°F | 22 km |
| 85634 | 9a | 20 to 25°F | 40 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 USC00024675, at 31.9603, -111.5978, elevation 2070 m (6,790 ft).
- Data quality: Representative (10+ years), 21 years of freeze data.
- Average days per year at or below 32°F: 59.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Anvil Rch (20 km)
- Tucson 17 NW (50 km)
- Tucson 11 W (51 km)
- Sasabe (53 km)
- Green Valley (57 km)
- Tucson Intl Airport (63 km)
- Tucson U Of A #1 (65 km)
- Tucson WFO (68 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.