Last spring frost
Feb 20
Frost Dates for San Antonio, TX
First fall frost
Dec 3
Growing season
291 days
Hardiness zone
9a
In an average year around San Antonio, TX, the last spring frost (32°F) is about Feb 20 and the first fall frost is about Dec 3, giving roughly a 291-day growing season. To be safe most years, wait until Jan 20 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Mar 27 | Mar 5 | Feb 8 |
| Freeze (32°F) | Mar 13 | Feb 20 | Jan 20 |
| Hard (28°F) | Mar 5 | Jan 30 | Dec 25 |
| Severe (24°F) | Feb 20 | Jan 14 | Dec 20 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 27 | Mar 19 | Mar 13 | Mar 9 | Mar 5 | Mar 1 | Feb 25 | Feb 18 | Feb 8 |
| 32°F | Mar 13 | Mar 7 | Mar 2 | Feb 26 | Feb 20 | Feb 14 | Feb 5 | Jan 30 | Jan 20 |
| 28°F | Mar 5 | Feb 24 | Feb 14 | Feb 4 | Jan 30 | Jan 23 | Jan 17 | Jan 6 | Dec 25 |
| 24°F | Feb 20 | Feb 5 | Jan 29 | Jan 22 | Jan 14 | Jan 8 | Jan 4 | Dec 30 | Dec 20 |
| 20°F | Feb 14 | Jan 29 | Jan 19 | Jan 10 | Jan 7 | Jan 5 | Jan 3 | Jan 1 | Dec 29 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Nov 2 | Nov 21 | Dec 9 |
| Freeze (32°F) | Nov 12 | Dec 3 | Jan 1 |
| Hard (28°F) | Nov 24 | Dec 23 | Jan 24 |
| Severe (24°F) | Dec 9 | Jan 5 | Feb 5 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 2 | Nov 8 | Nov 13 | Nov 17 | Nov 21 | Nov 25 | Nov 30 | Dec 3 | Dec 9 |
| 32°F | Nov 12 | Nov 20 | Nov 25 | Nov 29 | Dec 3 | Dec 7 | Dec 13 | Dec 20 | Jan 1 |
| 28°F | Nov 24 | Dec 1 | Dec 9 | Dec 16 | Dec 23 | Dec 30 | Jan 2 | Jan 8 | Jan 24 |
| 24°F | Dec 9 | Dec 20 | Dec 27 | Jan 1 | Jan 5 | Jan 8 | Jan 12 | Jan 22 | Feb 5 |
| 20°F | Dec 21 | Jan 1 | Jan 2 | Jan 4 | Jan 6 | Jan 8 | Jan 10 | Jan 20 | Feb 9 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: San Antonio Stinson Ap, Tx, about 2.9 miles away@if(!empty($station['elevation_ft'])), at 571 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in San Antonio, TX?
On average, the last spring frost (32°F) around San Antonio, TX is about Feb 20. In cooler years it can run later, so for a safer bet many gardeners wait until Jan 20.
When is the first frost in the fall?
The first fall frost around San Antonio, TX typically arrives about Dec 3. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around Feb 20 on average, or Jan 20 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 291 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 78221 Planting calendar → Texas frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026