Rio Grande City, TX Frost Dates & Growing Season

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

Last spring frost
Jan 31
~50% chance of frost after
First fall frost
Dec 17
~50% chance of frost before
Growing season
320 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 29 Jan 31 Mar 4
First fall frost Jan 20 Dec 17 Nov 22
Hard freeze (28°F), median last Jan 12 · first Dec 29

Computed from NOAA 1991–2020 climate normals at the RIO GRANDE CITY 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 Rio Grande City

Computed from Rio Grande City'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 6 – Dec 20 Feb 7 – Feb 14
🫑 Peppers Nov 22 – Dec 6 Feb 14 – Feb 21
🥬 Lettuce Dec 20 – Jan 3 Jan 3 – Jan 17 Jan 3 – Jan 31
🫛 Peas Dec 20 – Jan 3
🥕 Carrots Jan 10 – Jan 31
🥦 Broccoli Dec 13 – Dec 27 Jan 10 – Jan 24
🥬 Kale Dec 20 – Jan 3 Jan 3 – Jan 17 Jan 3 – Jan 17
🥒 Cucumbers Jan 3 – Jan 10 Feb 7 – Feb 14 Feb 7 – Feb 14
🥒 Zucchini Jan 3 – Jan 10 Feb 7 – Feb 14 Feb 7 – Feb 14
🫘 Green Beans (Bush) Feb 7 – Feb 14
🌽 Sweet Corn Feb 7 – Feb 14
🌿 Basil Dec 20 – Jan 3 Feb 7 – Feb 14 Feb 14 – Feb 21
🧄 Garlic Fall: Nov 5 – Dec 3

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 Rio Grande City's dates automatically after a lookup.

Reading the season in Rio Grande City

With roughly 320 frost-free days, Rio Grande City 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 17 is late enough that fall planting is a full second season, not an afterthought.

Frequently asked questions

When is the last frost in Rio Grande City, TX?

The average last spring frost in Rio Grande City is around Jan 31, 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 Rio Grande City, TX?

The average first fall frost in Rio Grande City arrives around Dec 17. 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 Rio Grande City?

About 320 frost-free days on average, from Jan 31 to Dec 17. That comfortably fits long-season crops like melons and winter squash, plus spring and fall plantings of cool-season vegetables.

What USDA zone is Rio Grande City 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.