Port Arthur, TX planting zone & frost dates
Port Arthur is in USDA hardiness zone 9b. The last spring frost usually comes around February 14 and the first fall frost around December 7, for a growing season of about 301 days.
Planting calendar for Port Arthur
Dates are counted from the average last spring frost (February 14) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.
| Crop | When |
|---|---|
| Tomatoes | Start seeds indoors: Dec 20 – Jan 3 Transplant outdoors: Feb 21 – Feb 28 |
| Peppers | Start seeds indoors: Dec 6 – Dec 20 Transplant outdoors: Feb 28 – Mar 7 |
| Eggplant | Start seeds indoors: Dec 6 – Dec 20 Transplant outdoors: Feb 28 – Mar 7 |
| Broccoli | Start seeds indoors: Dec 6 – Dec 20 Transplant outdoors: Jan 17 – Jan 31 |
| Cabbage | Start seeds indoors: Dec 6 – Dec 20 Transplant outdoors: Jan 17 – Jan 31 |
| Onions (sets) | Plant outdoors: Jan 17 – Jan 31 |
| Peas | Sow outdoors: Jan 3 – Jan 17 |
| Spinach | Sow outdoors: Jan 3 – Jan 17 |
| Lettuce | Sow outdoors: Jan 17 – Jan 31 |
| Carrots | Sow outdoors: Jan 17 – Jan 31 |
| Potatoes | Plant outdoors: Jan 17 – Jan 31 |
| Beans | Sow outdoors: Feb 21 – Feb 28 |
| Sweet corn | Sow outdoors: Feb 21 – Feb 28 |
| Cucumbers | Sow outdoors: Feb 21 – Feb 28 |
| Squash & zucchini | Sow outdoors: Feb 21 – Feb 28 |
| Basil | Start seeds indoors: Jan 3 – Jan 17 Transplant outdoors: Feb 21 – Feb 28 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Oct 12 (8 weeks before the average first fall frost on Dec 7).
Useful for zone 9b gardens
- Seed starting kit with dome — to start seeds indoors before the last frost
- LED grow light for seedlings — stops leggy seedlings
- Frost cloth / plant covers — for late spring and early fall frosts
- Soil thermometer — warm-season crops need soil above 60°F
- Shade cloth — for hot summers
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Jan 17 | Feb 14 | Mar 13 |
| First 32°F frost in fall is before | Jan 9 | Dec 7 | Nov 15 |
How to read it: in spring there is a 10% chance of a frost after March 13, so that is a safe date for tender plants. In fall there is a 10% chance of frost before November 15. A hard freeze (28°F) usually ends around January 28.
Hardiness zone by ZIP code in Port Arthur
- 77640 zone 9b
- 77641 zone 9b
- 77642 zone 9b
- 77643 zone 9b
Nearby cities
Questions
What growing zone is Port Arthur, TX?
Port Arthur is in USDA Plant Hardiness Zone 9b (average extreme winter low 25°F to 30°F), according to the USDA 2023 map.
When is the last frost in Port Arthur?
The average last spring frost (32°F) in Port Arthur is February 14. There is still a 10% chance of frost until March 13.
When can I plant tomatoes in Port Arthur?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Feb 21 – Feb 28. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Port Arthur Se Tx Ap, TX (USW00012917), 10.5 km (6.5 mi) from the city center, elevation 5 m, based on 28 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.