San Antonio-Seaworld, TX Frost Dates & Growing Season

The two dates every San Antonio-Seaworld garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
Feb 18
~50% chance of frost after
First fall frost
Dec 9
~50% chance of frost before
Growing season
294 days
frost-free stretch
USDA zone
≈ 9a
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Jan 18 Feb 18 Mar 16
First fall frost Jan 13 Dec 9 Nov 17
Hard freeze (28°F), median last Jan 31 · first Dec 29

Computed from NOAA 1991–2020 climate normals at the SAN ANTONIO/SEAWORLD station. "Safe" means frost past that date happens only about one year in ten. Your exact garden can still run days either way with elevation and terrain — check your own ZIP with the frost date lookup.

Planting windows for San Antonio-Seaworld

Computed from San Antonio-Seaworld's own frost dates. Click any crop for the full zone-9 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Dec 24 – Jan 7 Feb 25 – Mar 4
🫑 Peppers Dec 10 – Dec 24 Mar 4 – Mar 11
🥬 Lettuce Jan 7 – Jan 21 Jan 21 – Feb 4 Jan 21 – Feb 18
🫛 Peas Jan 7 – Jan 21
🥕 Carrots Jan 28 – Feb 18
🥦 Broccoli Dec 31 – Jan 14 Jan 28 – Feb 11
🥬 Kale Jan 7 – Jan 21 Jan 21 – Feb 4 Jan 21 – Feb 4
🥒 Cucumbers Jan 21 – Jan 28 Feb 25 – Mar 4 Feb 25 – Mar 4
🥒 Zucchini Jan 21 – Jan 28 Feb 25 – Mar 4 Feb 25 – Mar 4
🫘 Green Beans (Bush) Feb 25 – Mar 4
🌽 Sweet Corn Feb 25 – Mar 4
🌿 Basil Jan 7 – Jan 21 Feb 25 – Mar 4 Mar 4 – Mar 11
🧄 Garlic Fall: Oct 28 – Nov 25

Want this for all 50 crops, or as a printable seed-shelf schedule? Use the planting calendar and the seed starting scheduler — both can use San Antonio-Seaworld's dates automatically after a lookup.

Reading the season in San Antonio-Seaworld

With roughly 294 frost-free days, San Antonio-Seaworld gardens fit long-season crops — melons, winter squash, sweet potatoes — with room left for spring and fall rounds of greens and roots. The first frost around Dec 9 is late enough that fall planting is a full second season, not an afterthought.

Frequently asked questions

When is the last frost in San Antonio-Seaworld, TX?

The average last spring frost in San Antonio-Seaworld is around Feb 18, based on 1991–2020 climate normals. That's a median — about half of years see a later frost, so tender crops are safest going out a week or two after this date.

When is the first frost in San Antonio-Seaworld, TX?

The average first fall frost in San Antonio-Seaworld arrives around Dec 9. Crops still in the garden need to mature before then, and frost-tender plants need harvesting or protection as the date approaches.

How long is the growing season in San Antonio-Seaworld?

About 294 frost-free days on average, from Feb 18 to Dec 9. That comfortably fits long-season crops like melons and winter squash, plus spring and fall plantings of cool-season vegetables.

What USDA zone is San Antonio-Seaworld in?

USDA zone 9a on the 2023 Plant Hardiness Zone Map. Note that zones describe winter cold, not frost timing — these frost dates are the numbers to plan plantings around.