Frost dates for Randolph AFB, TX
At Randolph AFB, the median last spring frost (32°F) is Feb 21 and the median first fall frost is Dec 5, for a typical growing season of 289 days. For a 90% chance that the last frost has passed, wait until Mar 14. Nearby ZIP codes are in USDA hardiness zone 9a.
- Feb 21Last spring frost (median)50% chance of 32°F after this date
- Mar 14Safer planting date10% chance of 32°F after this date
- Dec 5First fall frost (median)50% chance of 32°F by this date
- 289 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 6 | Mar 26 |
| 32°F | Jan 10 | Feb 21 | Mar 14 |
| 28°F | Dec 18 | Jan 26 | Mar 5 |
| 24°F | Dec 11 | Jan 4 | Feb 24 |
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 4 | Nov 24 | Dec 10 |
| 32°F | Nov 16 | Dec 5 | Jan 1 |
| 28°F | Nov 28 | Dec 19 | Feb 1 |
| 24°F | Dec 6 | Dec 28 | Feb 11 |
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 | 232 days | 261 days | 291 days |
| 32°F | 259 days | 289 days | 331 days |
| 28°F | 288 days | 336 days | 365 days |
| 24°F | 328 days | 365 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 99% |
| 28°F | 83% |
| 24°F | 41% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 78154 | 9a | 20 to 25°F | 1 km |
| 78148 | 9a | 20 to 25°F | 2 km |
| 78108 | 9a | 20 to 25°F | 6 km |
| 78109 | 9a | 20 to 25°F | 8 km |
| 78233 | 9a | 20 to 25°F | 9 km |
| 78239 | 9a | 20 to 25°F | 9 km |
| 78244 | 9a | 20 to 25°F | 11 km |
| 78266 | 9a | 20 to 25°F | 13 km |
| 78152 | 9a | 20 to 25°F | 14 km |
| 78101 | 9a | 20 to 25°F | 21 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 USW00012911, at 29.5439, -98.2736, elevation 232 m (760 ft).
- Data quality: Estimated from nearby stations (2+ years), 2 years of freeze data.
- Average days per year at or below 32°F: 12.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- New Braunfels (17 km)
- San Antonio Intl Airport (20 km)
- San Antonio Incarnate Word (21 km)
- Austin San Antonio (30 km)
- New Braunfels WFO (30 km)
- San Antonio Stinson Airport (30 km)
- San Antonio Kelly AFB (35 km)
- Canyon Dam (36 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.