Frost dates for Sonoita, AZ
At Sonoita, the median last spring frost (32°F) is Mar 28 and the median first fall frost is Nov 21, for a typical growing season of 237 days. For a 90% chance that the last frost has passed, wait until Apr 21. Nearby ZIP codes are in USDA hardiness zone 8a.
- Mar 28Last spring frost (median)50% chance of 32°F after this date
- Apr 21Safer planting date10% chance of 32°F after this date
- Nov 21First fall frost (median)50% chance of 32°F by this date
- 237 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 26 | Apr 16 | May 4 |
| 32°F | Mar 1 | Mar 28 | Apr 21 |
| 28°F | Jan 29 | Mar 1 | Apr 4 |
| 24°F | Dec 25 | Feb 2 | Mar 3 |
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 25 | Nov 9 | Nov 25 |
| 32°F | Nov 5 | Nov 21 | Dec 7 |
| 28°F | Nov 16 | Dec 2 | Dec 23 |
| 24°F | Nov 27 | Dec 20 | Jan 26 |
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 | 183 days | 206 days | 231 days |
| 32°F | 207 days | 237 days | 268 days |
| 28°F | 237 days | 273 days | 313 days |
| 24°F | 279 days | 322 days | 361 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 94% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 85637 | 8a | 10 to 15°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 USC00027990, at 31.6811, -110.6553, elevation 1492 m (4,895 ft).
- Data quality: Estimated from nearby stations (2+ years), 6 years of freeze data.
- Average days per year at or below 32°F: 41.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Elgin 5 S (17 km)
- Canelo 1 NW (18 km)
- Santa Rita Exp. Range (20 km)
- Fort Huachuca Pioneer Airfield (23 km)
- Kartchner Caverns (33 km)
- Nogales Intl Airport (34 km)
- Nogales 6 N (39 km)
- Sierra Vista (39 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.