Frost dates for Austin San Antonio, TX
At Austin San Antonio, the median last spring frost (32°F) is Mar 1 and the median first fall frost is Nov 26, for a typical growing season of 273 days. For a 90% chance that the last frost has passed, wait until Mar 20. Nearby ZIP codes are in USDA hardiness zone 9a.
- Mar 1Last spring frost (median)50% chance of 32°F after this date
- Mar 20Safer planting date10% chance of 32°F after this date
- Nov 26First fall frost (median)50% chance of 32°F by this date
- 273 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 23 | Mar 13 | Apr 3 |
| 32°F | Feb 3 | Mar 1 | Mar 20 |
| 28°F | Jan 11 | Feb 13 | Mar 10 |
| 24°F | Dec 23 | Jan 26 | Mar 1 |
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 31 | Nov 15 | Dec 2 |
| 32°F | Nov 8 | Nov 26 | Dec 20 |
| 28°F | Nov 18 | Dec 11 | Jan 16 |
| 24°F | Dec 2 | Jan 1 | Feb 3 |
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 | 219 days | 246 days | 273 days |
| 32°F | 244 days | 273 days | 307 days |
| 28°F | 267 days | 306 days | 346 days |
| 24°F | 303 days | 345 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 97% |
| 24°F | 74% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 78123 | 9a | 20 to 25°F | 11 km |
| 78155 | 9a | 20 to 25°F | 20 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 USW00012971, at 29.7036, -98.0281, elevation 193 m (633 ft).
- Data quality: Representative (10+ years), 20 years of freeze data.
- Average days per year at or below 32°F: 20.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- New Braunfels WFO (0 km)
- New Braunfels (14 km)
- San Marcos (21 km)
- Canyon Dam (24 km)
- Randolph AFB (30 km)
- Luling (36 km)
- San Antonio Intl Airport (47 km)
- San Antonio Incarnate Word (50 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.