Port Arthur, TX Frost Dates
Published: February 1, 2026 · Updated: April 23, 2026
USDA Zone 9a
Last Spring Frost
January 30
Safe to transplant after this date
First Fall Frost
December 15
Protect tender plants before this date
Frost-Free Season
319 days
Year-round to Year-round
245 days until last frost in Port Arthur — January 30
Port Arthur’s zone 9a climate means frost is a minor consideration. Nearly year-round growing season. Frost possible but rare. Phoenix, Los Angeles, Central Florida. Rather than a single planting season, Port Arthur gardeners work almost year-round.
Complete Planting Calendar for Port Arthur
Lawn Care Timing for Port Arthur
Based on Port Arthur's USDA zone 9a frost dates: The last frost of January 30 marks when warm-season grasses begin recovering. Apply spring fertilizer in February when soil reaches 55°F. The first fall frost of December 15 sets your deadlines — complete overseeding by October–November and apply winterizer by Not typically needed.
USDA Zone 9a Summary
Nearly year-round growing season. Frost possible but rare. Phoenix, Los Angeles, Central Florida.
Frequently Asked Questions
What is the last frost date in Port Arthur, TX?
The average last spring frost in Port Arthur is January 30. This is based on USDA zone 9a historical averages. Plan transplanting and spring lawn care around this date — wait 2 weeks after for frost-sensitive plantings.
When is the first fall frost in Port Arthur?
Port Arthur’s average first fall frost is December 15. This sets deadlines for fall overseeding (must be done when temperatures cool) and winterizer application (by Not typically needed).
When should I plant tomatoes in Port Arthur?
Transplant tomato seedlings outdoors after January 30. Start seeds indoors September (for fall garden). Direct sow warm-season crops february–april.
When should I overseed my lawn in Port Arthur?
The prime overseeding window in Port Arthur is October–November. This ensures warm soil for germination before the first fall frost on December 15.
When should I apply winterizer in Port Arthur?
Apply winterizer fertilizer in Port Arthur by Not typically needed. This high-potassium application hardens grass cell walls before freeze damage. Your first fall frost of December 15 is the hard deadline.