Frost dates for San Antonio Kelly AFB, TX
At San Antonio Kelly AFB, the median last spring frost (32°F) is Feb 22 and the median first fall frost is Dec 2, for a typical growing season of 284 days. For a 90% chance that the last frost has passed, wait until Mar 12. Nearby ZIP codes are in USDA hardiness zone 9a.
- Feb 22Last spring frost (median)50% chance of 32°F after this date
- Mar 12Safer planting date10% chance of 32°F after this date
- Dec 2First fall frost (median)50% chance of 32°F by this date
- 284 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 13 | Mar 5 | Mar 27 |
| 32°F | Jan 16 | Feb 22 | Mar 12 |
| 28°F | Dec 23 | Feb 1 | Mar 3 |
| 24°F | Dec 11 | Jan 7 | Feb 21 |
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 3 | Nov 22 | Dec 7 |
| 32°F | Nov 13 | Dec 2 | Dec 25 |
| 28°F | Nov 25 | Dec 16 | Feb 1 |
| 24°F | Dec 5 | Dec 27 | 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 | 233 days | 258 days | 285 days |
| 32°F | 255 days | 284 days | 325 days |
| 28°F | 279 days | 322 days | 365 days |
| 24°F | 320 days | 362 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 90% |
| 24°F | 52% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 78226 | 9a | 20 to 25°F | 1 km |
| 78243 | 9a | 20 to 25°F | 2 km |
| 78236 | 9a | 20 to 25°F | 4 km |
| 78242 | 9a | 20 to 25°F | 4 km |
| 78237 | 9a | 20 to 25°F | 4 km |
| 78211 | 9a | 20 to 25°F | 5 km |
| 78227 | 9a | 20 to 25°F | 5 km |
| 78225 | 9a | 20 to 25°F | 6 km |
| 78207 | 9a | 20 to 25°F | 7 km |
| 78204 | 9a | 20 to 25°F | 8 km |
| 78228 | 9a | 20 to 25°F | 9 km |
| 78252 | 9a | 20 to 25°F | 12 km |
| 78073 | 9a | 20 to 25°F | 16 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 USW00012909, at 29.3833, -98.5833, elevation 208 m (682 ft).
- Data quality: Estimated from nearby stations (2+ years), 2 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 Stinson Airport (12 km)
- San Antonio/seaworld (14 km)
- San Antonio Incarnate Word (14 km)
- San Antonio Intl Airport (20 km)
- Lytle 3w (30 km)
- Randolph AFB (35 km)
- Poteet (40 km)
- Pleasanton (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.