Frost dates for Santa Rita Exp. Range, AZ
At Santa Rita Exp. Range, the median last spring frost (32°F) is Feb 25 and the median first fall frost is Dec 5, for a typical growing season of 282 days. For a 90% chance that the last frost has passed, wait until Mar 29. Nearby ZIP codes are in USDA hardiness zone 9a.
- Feb 25Last spring frost (median)50% chance of 32°F after this date
- Mar 29Safer planting date10% chance of 32°F after this date
- Dec 5First fall frost (median)50% chance of 32°F by this date
- 282 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 | Feb 26 | Mar 22 | Apr 16 |
| 32°F | Jan 24 | Feb 25 | Mar 29 |
| 28°F | Dec 20 | Jan 28 | Feb 24 |
| 24°F | Dec 7 | Jan 6 | Feb 7 |
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 | Nov 1 | Nov 23 | Dec 9 |
| 32°F | Nov 16 | Dec 5 | Dec 22 |
| 28°F | Nov 27 | Dec 19 | Jan 27 |
| 24°F | Dec 5 | Jan 2 | Feb 5 |
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 | 212 days | 243 days | 272 days |
| 32°F | 247 days | 282 days | 320 days |
| 28°F | 292 days | 332 days | 365 days |
| 24°F | 331 days | 365 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 88% |
| 24°F | 37% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 85614 | 9a | 20 to 25°F | 10 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 USC00027593, at 31.7625, -110.8464, elevation 1311 m (4,300 ft).
- Data quality: Representative (10+ years), 17 years of freeze data.
- Average days per year at or below 32°F: 17.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Sonoita (20 km)
- Green Valley (20 km)
- Tumacacori National Monument (29 km)
- Nogales 6 N (36 km)
- Elgin 5 S (37 km)
- Canelo 1 NW (38 km)
- Nogales Intl Airport (38 km)
- Tucson Intl Airport (42 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.