Frost dates for San Antonio, Texas
In San Antonio, half of springs have had their last frost by February 26 (and 1 spring in 10 still has one after March 17), and half of falls have had their first frost by November 28, leaving about 277 frost-free days in a typical year. Here is how sure those dates are, what they mean for planting, and where they come from.
Frost dates for
San Antonio, Texas
Last spring frost
February 26
Half of springs have their last frost by this date. For a safer bet, wait until March 17: only 1 spring in 10 has a frost after that.
First fall frost
November 28
Half of falls have their first frost by this date. In 1 fall in 10 it comes by November 7.
Growing season
277 days
Frost-free days in a typical year. 9 years in 10 get at least 247.
Hardiness zone
9a
2023 USDA map: the coldest night of winter averages 20°F to 25°F. On the 2012 map it was 8b, half a zone colder. All 21 ZIP codes within about 6 miles of the city's center are in zone 9a.
Print a year planner for San Antonio
Frost risk through the year
How sure are these dates?
A frost date is a probability, not a promise. NOAA worked out, from 30 years of nightly lows, how often the last spring frost and the first fall frost fall on each date. The middle column is the typical year. The outer columns are the early and late years that come about once a decade.
| Early year 1 in 10 | Typical year 1 in 2 | Late year 1 in 10 | |
|---|---|---|---|
| Last frost in spring | January 29 | February 26 | March 17 |
| First frost in fall | November 7 | November 28 | December 22 |
The frost-free season between them runs 277 days in a typical year. In 1 year in 10 it is 311 days or longer, and in 1 year in 10 it is 247 days or shorter.
- Hard freeze (28°F): about 96 years in 100 have one. In those years the last typically comes on February 9 and the first on December 13. It is a harder freeze than the 32°F frost line, cold enough to damage many garden plants; how hardy a crop is decides whether it comes through. (The National Weather Service's own hard-freeze threshold varies from office to office.)
- Frost possible (36°F at the station): typically last on March 10 and first on November 16. On clear, still nights the ground can be several degrees colder than the thermometer, so frost can form on plants when the official reading is in the mid-30s.
In 8 springs out of 10, the last frost in San Antonio comes between January 29 and March 17, a window of 47 days. That is wider than at most NOAA stations (the typical window is 31 days), so spring here is less predictable than average: lean toward the later date.
Among Texas's 387 NOAA stations with a frost every year, 92 percent have their typical last frost later than San Antonio does.
Planting calendar for San Antonio
These dates count from the typical last and first frosts, using the planting rules published by Colorado State University Extension (spring), Virginia Cooperative Extension (fall crops) and University of Minnesota Extension (garlic, where winters are hard). Weather in any one year can run early or late, so check the forecast before you plant tender crops.
We don't give a garlic date here. The rule we use, from the University of Minnesota Extension, counts from the first killing frost, and it works where a hard freeze comes every year before the ground freezes. Your county's extension office can tell you when to plant garlic in your climate.
| When | What to do | Why then |
|---|---|---|
| January | ||
| January 8 to 29 | Eggplant Start seeds indoors | 6 to 9 weeks before planting out |
| January 15 to 29 | Peppers Start seeds indoors | 6 to 8 weeks before planting out |
| January 22 to February 5 | Tomatoes Start seeds indoors | 5 to 7 weeks before planting out |
| January 29 to February 12 | Peas, spinach, lettuce, radishes, onion sets, turnips Sow outdoors, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| January 29 to February 12 | Broccoli and cabbage Plant out, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| February | ||
| February 12 to 26 | Beets, carrots, potatoes, Swiss chard Plant outdoors, as early as | semi-hardy crops: up to 2 weeks before the typical last frost |
| February 12 to 26 | Cauliflower Plant out, as early as | semi-hardy: up to 2 weeks before the typical last frost |
| February 26 | Snap beans, sweet corn, cucumbers, summer squash Sow outdoors around | tender crops: around the typical last frost date |
| March | ||
| March 12 | Tomatoes, peppers, eggplant Plant out from | very tender: 2 weeks or more after the typical last frost |
| March 12 | Melons, winter squash, pumpkins, lima beans Sow outdoors from | very tender: 2 weeks or more after the typical last frost |
| July | ||
| July 3 to 17 | Cabbage for fall Start seeds | set the plants out by August 21 |
| July 23 to August 6 | Broccoli for fall Start seeds | set the plants out by September 10 |
| September | ||
| September 1 | Snap beans for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| September 5 | Carrots for fall Last date to sow | 70 days to harvest, plus 2 weeks for slower fall growth |
| September 6 | Cucumbers for fall Last date to sow | 55 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| September 10 | Peas for fall Last date to sow | 65 days to harvest, plus 2 weeks for slower fall growth |
| September 11 | Summer squash for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| September 15 | Leaf lettuce and beets for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth |
| September 25 | Turnips and kohlrabi for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth |
| October | ||
| October 5 | Spinach for fall Last date to sow | 40 days to harvest, plus 2 weeks for slower fall growth |
| October 15 | Radishes for fall Last date to sow | 30 days to harvest, plus 2 weeks for slower fall growth |
| November | ||
| November 7 | Tomatoes, peppers, squash, melons, cucumbers Watch the forecast from | in 1 fall in 10 the first frost comes by this date; pick tender crops before a frost |
| December | ||
| December 11 to January 8 | Broccoli and cabbage Start seeds indoors | 5 to 7 weeks before planting them out |
| December 25 to January 22 | Cauliflower Start seeds indoors | 5 to 7 weeks before planting out |
Want more insurance? Shift every spring date 19 days later. That plans around March 17, the date after which only 1 spring in 10 has a frost.
For spring bulbs such as tulips and daffodils, plant once the soil has cooled to about 50 to 55°F and keep going until a couple of weeks before the ground freezes. Our guide to fall planting explains how to tell.
Where these numbers come from
These dates come from NOAA's weather station San Antonio International Airport (station USW00012921), 6 miles from the center of San Antonio. It sits at about the same elevation, 790 feet above sea level. NOAA rates this station's record as standard: at least 24 of the 30 years, with gaps filled from nearby stations.
The same station also gives the frost dates for Schertz, Converse, Universal City, Live Oak, Selma, Leon Valley and Helotes.
Our ZIP code lookup matches these 13 ZIP codes to the same station, so they get the same dates: 78209, 78213, 78216, 78217, 78230, 78231, 78232, 78233, 78239, 78247, 78248, 78259, 78266. Hardiness zones are worked out separately for each ZIP code.
Nearby places
- New Braunfels, Texas: last frost around March 1, first frost around November 26 (30 miles away)
- Austin, Texas: frost not every year (75 miles away)
- Killeen, Texas: last frost around March 14, first frost around November 17 (120 miles away)
See frost dates across Texas, or look up your own ZIP code for the station nearest you. Want the background? Read what a last frost date really means.