Frost dates for Alamo Dam, AZ
At Alamo Dam, the median last spring frost (32°F) is Mar 4 and the median first fall frost is Nov 23, for a typical growing season of 261 days. For a 90% chance that the last frost has passed, wait until Mar 31. Nearby ZIP codes are in USDA hardiness zones 9a to 10a.
- Mar 4Last spring frost (median)50% chance of 32°F after this date
- Mar 31Safer planting date10% chance of 32°F after this date
- Nov 23First fall frost (median)50% chance of 32°F by this date
- 261 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 4 | Mar 23 | Apr 14 |
| 32°F | Feb 13 | Mar 4 | Mar 31 |
| 28°F | Jan 18 | Feb 13 | Mar 5 |
| 24°F | Dec 23 | Jan 19 | Feb 15 |
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 29 | Nov 12 | Nov 23 |
| 32°F | Nov 10 | Nov 23 | Dec 4 |
| 28°F | Nov 21 | Dec 3 | Dec 19 |
| 24°F | Dec 1 | Dec 17 | Jan 8 |
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 | 204 days | 229 days | 255 days |
| 32°F | 233 days | 261 days | 284 days |
| 28°F | 269 days | 294 days | 324 days |
| 24°F | 302 days | 335 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 91% |
Closest ZIP codes (each is closer to another station)
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 85357 | 9a | 20 to 25°F | 26 km |
| 85360 | 9b | 25 to 30°F | 36 km |
| 85325 | 9a | 20 to 25°F | 40 km |
| 86406 | 10a | 30 to 35°F | 49 km |
| 85320 | 9a | 20 to 25°F | 54 km |
| 86321 | 9a | 20 to 25°F | 58 km |
| 92267 | 10a | 30 to 35°F | 58 km |
| 85348 | 9a | 20 to 25°F | 59 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 USC00020100, at 34.2281, -113.5778, elevation 393 m (1,290 ft).
- Data quality: Representative (10+ years), 25 years of freeze data.
- Average days per year at or below 32°F: 28.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Aguila (48 km)
- Bouse (52 km)
- Wikieup (53 km)
- Bagdad (55 km)
- Parker (66 km)
- Lake Havasu City (78 km)
- Wickenburg (82 km)
- Quartzsite (87 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.