Port Isabel, TX Frost Dates & Growing Season

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

Last spring frost
Jan 3
~50% chance of frost after
First fall frost
Jan 1
~50% chance of frost before
Growing season
363 days
frost-free stretch
USDA zone
≈ 9b
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Dec 11 Jan 3 Feb 2
First fall frost Feb 1 Jan 1 Dec 7
Hard freeze (28°F), median last Jan 2 · first Jan 1

Computed from NOAA 1991–2020 climate normals at the PORT ISABEL 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 Port Isabel

Computed from Port Isabel'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 Nov 8 – Nov 22 Jan 10 – Jan 17
🫑 Peppers Oct 25 – Nov 8 Jan 17 – Jan 24
🥬 Lettuce Nov 22 – Dec 6 Dec 6 – Dec 20 Dec 6 – Jan 3
🫛 Peas Nov 22 – Dec 6
🥕 Carrots Dec 13 – Jan 3
🥦 Broccoli Nov 15 – Nov 29 Dec 13 – Dec 27
🥬 Kale Nov 22 – Dec 6 Dec 6 – Dec 20 Dec 6 – Dec 20
🥒 Cucumbers Dec 6 – Dec 13 Jan 10 – Jan 17 Jan 10 – Jan 17
🥒 Zucchini Dec 6 – Dec 13 Jan 10 – Jan 17 Jan 10 – Jan 17
🫘 Green Beans (Bush) Jan 10 – Jan 17
🌽 Sweet Corn Jan 10 – Jan 17
🌿 Basil Nov 22 – Dec 6 Jan 10 – Jan 17 Jan 17 – Jan 24
🧄 Garlic Fall: Nov 20 – Dec 18

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 Port Isabel's dates automatically after a lookup.

Reading the season in Port Isabel

With roughly 363 frost-free days, Port Isabel 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 Jan 1 is late enough that fall planting is a full second season, not an afterthought.

Frequently asked questions

When is the last frost in Port Isabel, TX?

The average last spring frost in Port Isabel is around Jan 3, 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 Port Isabel, TX?

The average first fall frost in Port Isabel arrives around Jan 1. 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 Port Isabel?

About 363 frost-free days on average, from Jan 3 to Jan 1. That comfortably fits long-season crops like melons and winter squash, plus spring and fall plantings of cool-season vegetables.

What USDA zone is Port Isabel in?

USDA zone 9b 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.