Frost dates for 78220San Antonio, TX
The average last spring frost in San Antonio is February 25 and the average first fall frost is November 28, giving a typical growing season of about 277 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Feb 25
- Average first fall frost
- Nov 28
- Growing season
- 277 days
Safer after Mar 19 (1-in-10 risk)
Possible by Nov 7 (1-in-10 risk)
First frost typically in 28 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Feb 18 · Mar 10 · Apr 2 | Oct 30 · Nov 16 · Dec 3 | 251 days | 100% |
| Frost / freeze (32°F) | Jan 28 · Feb 25 · Mar 19 | Nov 7 · Nov 28 · Dec 21 | 277 days | 100% |
| Hard freeze (28°F) | Dec 31 · Feb 5 · Mar 5 | Nov 19 · Dec 15 · Jan 20 | 315 days | 95% |
Planting calendar for San Antonio
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Jan 25 – Apr 2 |
| Tomatoes | Transplant outdoors | Mar 13 – Aug 8 |
| Peppers | Start seeds indoors | Jan 25 – Feb 25 |
| Peppers | Transplant outdoors | Mar 27 – Apr 27 |
| Eggplant | Start seeds indoors | Feb 11 – Mar 12 |
| Eggplant | Transplant outdoors | Mar 27 – Apr 27 |
| Cucumbers | Sow outdoors | Mar 27 – Aug 18 |
| Summer squash | Sow outdoors | Mar 13 – Apr 27 |
| Winter squash & pumpkins | Sow outdoors | Mar 27 – Apr 27 |
| Snap beans | Sow outdoors | Mar 13 – Sep 10 |
| Sweet corn | Sow outdoors | Mar 13 – Aug 8 |
| Watermelon & cantaloupe | Sow outdoors | Mar 27 – Apr 27 |
| Okra | Sow outdoors | Mar 20 – Apr 12 |
| Peas | Sow outdoors (spring) | Jan 25 – Mar 12 |
| Potatoes | Plant outdoors (spring) | Jan 25 – Mar 27 |
| Onions | Start seeds indoors (spring) | Dec 14 – Jan 10 |
| Onions | Transplant outdoors (spring) | Feb 11 – Mar 12 |
| Broccoli | Start seeds indoors (spring) | Jan 7 – Feb 10 |
| Broccoli | Transplant outdoors (spring) | Feb 11 – Mar 12 |
| Broccoli | Start seeds indoors (fall) | Jul 29 – Aug 8 |
| Broccoli | Transplant outdoors (fall) | Aug 28 – Sep 8 |
| Cabbage | Start seeds indoors (spring) | Dec 28 – Jan 25 |
| Cabbage | Transplant outdoors (spring) | Jan 25 – Feb 25 |
| Cabbage | Start seeds indoors (fall) | Jul 19 – Aug 18 |
| Cabbage | Transplant outdoors (fall) | Aug 18 – Sep 18 |
| Leaf lettuce | Sow outdoors (spring) | Jan 25 – Apr 12 |
| Leaf lettuce | Sow outdoors (fall) | Aug 18 – Oct 4 |
| Spinach | Sow outdoors (spring) | Jan 18 – Mar 3 |
| Spinach | Sow outdoors (fall) | Sep 4 – Oct 9 |
| Radishes | Sow outdoors (spring) | Jan 25 – Mar 17 |
| Radishes | Sow outdoors (fall) | Aug 18 – Oct 19 |
| Kale | Sow outdoors (spring) | Feb 11 – Mar 3 |
| Kale | Sow outdoors (fall) | Aug 11 – Sep 18 |
| Carrots | Sow outdoors (spring) | Feb 25 – Apr 12 |
| Carrots | Sow outdoors (fall) | Jul 19 – Sep 3 |
| Garlic | Plant outdoors (fall) | Nov 18 – Dec 19 |
Where these dates come from
ZIP code 78220 is matched to the NOAA station San Antonio Incarnate Word, TX, 8.8 km away, at 700 ft elevation (54 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| San Antonio Incarnate Word, TX (used) | 700 ft | Feb 25 | Nov 28 |
| San Antonio Stinson Ap, TX | 571 ft | Feb 20 | Dec 3 |
| San Antonio Intl Ap, TX | 789 ft | Feb 26 | Nov 28 |
| San Antonio Kelly Afb, TX | 682 ft | Feb 22 | Dec 2 |
Frost dates near San Antonio
- San Antonio, TX 78222 · last Feb 20, first Dec 3
- Jbsa Ft Sam Houston, TX 78234 · last Feb 25, first Nov 28
- Jbsa Lackland, TX 78236 · last Feb 25, first Nov 28
- Adkins, TX 78101 · last Feb 20, first Dec 3
- Converse, TX 78109 · last Feb 25, first Nov 28
- Universal City, TX 78148 · last Feb 21, first Dec 5
- Elmendorf, TX 78112 · last Feb 20, first Dec 3
- Saint Hedwig, TX 78152 · last Feb 20, first Dec 3
Frequently asked questions
- When is the last frost in San Antonio, TX?
- For ZIP code 78220, the average last spring frost (32°F) is February 25, based on NOAA 1991-2020 climate normals for the San Antonio Incarnate Word, TX weather station. There is a 1-in-10 chance of a frost after March 19.
- When is the first frost in San Antonio, TX?
- The average first fall frost (32°F) is November 28. There is a 1-in-10 chance of frost by November 7, so tender plants are at risk from that point on.
- How long is the growing season in 78220?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 277 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.