Frost dates for 78225San Antonio, TX
The average last spring frost in San Antonio is February 20 and the average first fall frost is December 3, giving a typical growing season of about 291 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Feb 20
- Average first fall frost
- Dec 3
- Growing season
- 291 days
Safer after Mar 13 (1-in-10 risk)
Possible by Nov 12 (1-in-10 risk)
First frost typically in 31 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 8 · Mar 5 · Mar 27 | Nov 2 · Nov 21 · Dec 9 | 261 days | 100% |
| Frost / freeze (32°F) | Jan 20 · Feb 20 · Mar 13 | Nov 12 · Dec 3 · Jan 1 | 291 days | 100% |
| Hard freeze (28°F) | Dec 25 · Jan 30 · Mar 5 | Nov 24 · Dec 23 · Jan 24 | 330 days | 90% |
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 20 – Mar 28 |
| Tomatoes | Transplant outdoors | Mar 8 – Aug 13 |
| Peppers | Start seeds indoors | Jan 20 – Feb 20 |
| Peppers | Transplant outdoors | Mar 22 – Apr 22 |
| Eggplant | Start seeds indoors | Feb 6 – Mar 7 |
| Eggplant | Transplant outdoors | Mar 22 – Apr 22 |
| Cucumbers | Sow outdoors | Mar 22 – Aug 23 |
| Summer squash | Sow outdoors | Mar 8 – Apr 22 |
| Winter squash & pumpkins | Sow outdoors | Mar 22 – Apr 22 |
| Snap beans | Sow outdoors | Mar 8 – Sep 15 |
| Sweet corn | Sow outdoors | Mar 8 – Aug 13 |
| Watermelon & cantaloupe | Sow outdoors | Mar 22 – Apr 22 |
| Okra | Sow outdoors | Mar 15 – Apr 7 |
| Peas | Sow outdoors (spring) | Jan 20 – Mar 7 |
| Potatoes | Plant outdoors (spring) | Jan 20 – Mar 22 |
| Onions | Start seeds indoors (spring) | Dec 9 – Jan 5 |
| Onions | Transplant outdoors (spring) | Feb 6 – Mar 7 |
| Broccoli | Start seeds indoors (spring) | Jan 2 – Feb 5 |
| Broccoli | Transplant outdoors (spring) | Feb 6 – Mar 7 |
| Broccoli | Start seeds indoors (fall) | Aug 3 – Aug 13 |
| Broccoli | Transplant outdoors (fall) | Sep 2 – Sep 13 |
| Cabbage | Start seeds indoors (spring) | Dec 23 – Jan 20 |
| Cabbage | Transplant outdoors (spring) | Jan 20 – Feb 20 |
| Cabbage | Start seeds indoors (fall) | Jul 24 – Aug 23 |
| Cabbage | Transplant outdoors (fall) | Aug 23 – Sep 23 |
| Leaf lettuce | Sow outdoors (spring) | Jan 20 – Apr 7 |
| Leaf lettuce | Sow outdoors (fall) | Aug 23 – Oct 9 |
| Spinach | Sow outdoors (spring) | Jan 13 – Feb 26 |
| Spinach | Sow outdoors (fall) | Sep 9 – Oct 14 |
| Radishes | Sow outdoors (spring) | Jan 20 – Mar 12 |
| Radishes | Sow outdoors (fall) | Aug 23 – Oct 24 |
| Kale | Sow outdoors (spring) | Feb 6 – Feb 26 |
| Kale | Sow outdoors (fall) | Aug 16 – Sep 23 |
| Carrots | Sow outdoors (spring) | Feb 20 – Apr 7 |
| Carrots | Sow outdoors (fall) | Jul 24 – Sep 8 |
| Garlic | Plant outdoors (fall) | Nov 23 – Dec 24 |
Where these dates come from
ZIP code 78225 is matched to the NOAA station San Antonio Stinson Ap, TX, 7.4 km away, at 571 ft elevation (79 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| San Antonio Stinson Ap, TX (used) | 571 ft | Feb 20 | Dec 3 |
| San Antonio Kelly Afb, TX | 682 ft | Feb 22 | Dec 2 |
| San Antonio Incarnate Word, TX | 700 ft | Feb 25 | Nov 28 |
| San Antonio Intl Ap, TX | 789 ft | Feb 26 | Nov 28 |
Frost dates near San Antonio
- San Antonio, TX 78204 · 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
- Macdona, TX 78054 · last Feb 20, first Dec 3
- Von Ormy, TX 78073 · last Feb 20, first Dec 3
- Elmendorf, TX 78112 · last Feb 20, first Dec 3
- Somerset, TX 78069 · last Feb 20, first Dec 3
- Converse, TX 78109 · last Feb 25, first Nov 28
Frequently asked questions
- When is the last frost in San Antonio, TX?
- For ZIP code 78225, the average last spring frost (32°F) is February 20, based on NOAA 1991-2020 climate normals for the San Antonio Stinson Ap, TX weather station. There is a 1-in-10 chance of a frost after March 13.
- When is the first frost in San Antonio, TX?
- The average first fall frost (32°F) is December 3. There is a 1-in-10 chance of frost by November 12, so tender plants are at risk from that point on.
- How long is the growing season in 78225?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 291 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.