Frost dates for San Antonio Intl Airport, TX
At San Antonio Intl Airport, the median last spring frost (32°F) is Feb 26 and the median first fall frost is Nov 28, for a typical growing season of 277 days. For a 90% chance that the last frost has passed, wait until Mar 17. Nearby ZIP codes are in USDA hardiness zones 8b to 9a.
- Feb 26Last spring frost (median)50% chance of 32°F after this date
- Mar 17Safer planting date10% chance of 32°F after this date
- Nov 28First fall frost (median)50% chance of 32°F by this date
- 277 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 20 | Mar 10 | Apr 2 |
| 32°F | Jan 29 | Feb 26 | Mar 17 |
| 28°F | Jan 2 | Feb 9 | Mar 7 |
| 24°F | Dec 17 | Jan 22 | Feb 26 |
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 1 | Nov 16 | Dec 5 |
| 32°F | Nov 7 | Nov 28 | Dec 22 |
| 28°F | Nov 21 | Dec 13 | Jan 19 |
| 24°F | Dec 2 | Jan 1 | Feb 10 |
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 | 223 days | 251 days | 279 days |
| 32°F | 247 days | 277 days | 311 days |
| 28°F | 273 days | 311 days | 349 days |
| 24°F | 307 days | 352 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 96% |
| 24°F | 66% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 78216 | 9a | 20 to 25°F | 1 km |
| 78213 | 9a | 20 to 25°F | 5 km |
| 78232 | 9a | 20 to 25°F | 5 km |
| 78217 | 9a | 20 to 25°F | 6 km |
| 78248 | 9a | 20 to 25°F | 6 km |
| 78231 | 9a | 20 to 25°F | 7 km |
| 78230 | 9a | 20 to 25°F | 7 km |
| 78247 | 9a | 20 to 25°F | 8 km |
| 78229 | 9a | 20 to 25°F | 10 km |
| 78258 | 9a | 20 to 25°F | 10 km |
| 78259 | 9a | 20 to 25°F | 11 km |
| 78240 | 9a | 20 to 25°F | 12 km |
| 78249 | 9a | 20 to 25°F | 13 km |
| 78257 | 9a | 20 to 25°F | 15 km |
| 78256 | 9a | 20 to 25°F | 16 km |
| 78260 | 8b | 15 to 20°F | 17 km |
| 78261 | 9a | 20 to 25°F | 18 km |
| 78163 | 8b | 15 to 20°F | 25 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 USW00012921, at 29.5442, -98.4839, elevation 240 m (789 ft).
- Data quality: Standard (24+ years of data), 27 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
- San Antonio Incarnate Word (8 km)
- San Antonio Kelly AFB (20 km)
- Randolph AFB (20 km)
- San Antonio Stinson Airport (23 km)
- San Antonio/seaworld (24 km)
- New Braunfels (34 km)
- Boerne (37 km)
- Canyon Dam (45 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.