Frost dates for Casa Grande, AZ
At Casa Grande, the median last spring frost (32°F) is Feb 5 and the median first fall frost is Dec 6, for a typical growing season of 305 days. For a 90% chance that the last frost has passed, wait until Feb 28. Nearby ZIP codes are in USDA hardiness zone 9a.
- Feb 5Last spring frost (median)50% chance of 32°F after this date
- Feb 28Safer planting date10% chance of 32°F after this date
- Dec 6First fall frost (median)50% chance of 32°F by this date
- 305 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 | Jan 31 | Feb 26 | Mar 16 |
| 32°F | Jan 5 | Feb 5 | Feb 28 |
| 28°F | Dec 16 | Jan 14 | Feb 15 |
| 24°F | Dec 10 | Jan 6 | Feb 5 |
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 7 | Nov 24 | Dec 11 |
| 32°F | Nov 18 | Dec 6 | Dec 29 |
| 28°F | Nov 29 | Dec 22 | Jan 24 |
| 24°F | Dec 9 | Jan 1 | 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 | 243 days | 271 days | 299 days |
| 32°F | 273 days | 305 days | 340 days |
| 28°F | 304 days | 340 days | 365 days |
| 24°F | 340 days | 365 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 99% |
| 28°F | 79% |
| 24°F | 28% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 85122 | 9a | 20 to 25°F | 4 km |
| 85194 | 9a | 20 to 25°F | 8 km |
| 85193 | 9a | 20 to 25°F | 14 km |
| 85172 | 9a | 20 to 25°F | 23 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 USC00021306, at 32.8875, -111.7147, elevation 427 m (1,400 ft).
- Data quality: Representative (10+ years), 18 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
- Robson Rch (11 km)
- Arizona City (18 km)
- Casa Grande National Monument (20 km)
- Eloy 4 NE (22 km)
- Florence (35 km)
- Chandler Heights (36 km)
- Maricopa 4 N (39 km)
- Picacho 8 SE (40 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.