Frost dates for San Manuel, AZ
At San Manuel, the median last spring frost (32°F) is Feb 4 and the median first fall frost is Dec 8, for a typical growing season of 306 days. For a 90% chance that the last frost has passed, wait until Mar 2. Nearby ZIP codes are in USDA hardiness zone 9a.
- Feb 4Last spring frost (median)50% chance of 32°F after this date
- Mar 2Safer planting date10% chance of 32°F after this date
- Dec 8First fall frost (median)50% chance of 32°F by this date
- 306 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 2 | Mar 1 | Mar 30 |
| 32°F | Jan 5 | Feb 4 | Mar 2 |
| 28°F | Dec 17 | Jan 10 | Feb 11 |
| 24°F | Dec 17 | Jan 3 | Feb 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 | Nov 9 | Nov 25 | Dec 11 |
| 32°F | Nov 20 | Dec 8 | Dec 28 |
| 28°F | Dec 3 | Dec 22 | Jan 25 |
| 24°F | Dec 8 | Dec 31 | Jan 31 |
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 | 236 days | 268 days | 299 days |
| 32°F | 274 days | 306 days | 340 days |
| 28°F | 314 days | 346 days | 365 days |
| 24°F | 345 days | 365 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 78% |
| 24°F | 22% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 85631 | 9a | 20 to 25°F | 7 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 USC00027530, at 32.6014, -110.6292, elevation 1042 m (3,420 ft).
- Data quality: Estimated from nearby stations (2+ years), 10 years of freeze data.
- Average days per year at or below 32°F: 14.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Oracle State Park (10 km)
- Oracle 2 SE (10 km)
- Mount Lemmon Willow Canyon (25 km)
- Catalina State Park (35 km)
- Tohono Chul (44 km)
- Cascabel (46 km)
- Tucson Camp Ave Exp. (46 km)
- Saguaro National Park (48 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.