When is the last frost in Port Arthur, TX?

The average last spring frost (50% probability of 32°F) in Port Arthur is around February 14, based on NOAA/NCEI 1991–2020 normals at the Port Arthur Se Tx Ap, TX station (6.8 mi away). Half of years it falls outside that date, so wait 1–2 weeks past it before setting out frost-tender plants.

When is the first fall frost in Port Arthur?

The average first fall frost in Port Arthur, TX is around December 7, giving roughly a 301-day frost-free growing season.

What planting zone is Port Arthur, TX?

Port Arthur is in USDA plant hardiness zone 9b (average annual extreme minimum temperature 25 to 30°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in Port Arthur?

In Port Arthur, TX the warmest month is August (avg high 93.1°F) and the coldest is January (avg low 43.8°F). It averages about 62.1″ of precipitation a year.

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Port Arthur, TX Planting Calendar & Frost Dates

USDA hardiness zone 9b · ZIP 77640 · elevation 5′ · NOAA & USDA data

Port Arthur is in USDA hardiness zone 9b (winters can dip to 25 to 30°F), with a growing season of about 301 days between the average last spring frost (February 14) and first fall frost (December 7). The warmest month is August (avg high 93.1°F); the coldest is January (avg low 43.8°F). It averages 62.1″ of precipitation a year. Start cool-season crops several weeks before the last frost; wait until after it for tomatoes, peppers and other tender crops.

Hardiness zone

min temp 25 to 30°F

Last spring frost

February 14

avg (50% prob, 32°F)

First fall frost

December 7

avg (50% prob, 32°F)

Growing season

301 days

frost-free window

Warmest month

August

avg high 93.1°F

Month-by-month typical weather in Port Arthur

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Port Arthur Se Tx Ap, TX (6.8 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)	Snow (in)
January	63.5	43.8	53.7	5.3	–
February	67.3	47.8	57.5	3.1	–
March	73.2	53.4	63.3	3.6	–
April	79	59.6	69.3	3.9	–
May	85.7	67.3	76.5	4.7	–
June	90.9	73.1	82	6.7	–
July	92.6	74.6	83.6	6.9	–
August	93.1	74.4	83.8	6.9	–
September	89.5	70.6	80	6.7	–
October	82.1	61.1	71.6	5.5	–
November	72.3	51.5	61.9	3.9	–
December	65.5	45.8	55.6	5	–

What to plant when in Port Arthur

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: January 3 · Transplant out: February 21
Peppers	warm	Start seeds indoors: December 20 · Transplant out: February 28
Cucumbers	warm	Direct sow: February 21
Zucchini / squash	warm	Direct sow: February 21
Bush beans	warm	Direct sow: February 21
Sweet corn	warm	Direct sow: February 21
Basil	warm	Transplant out: February 21
Peas	cool	Sow (spring): January 10 · Sow (fall): October 12
Spinach	cool	Sow (spring): January 3 · Sow (fall): October 12
Lettuce	cool	Sow (spring): January 17 · Sow (fall): October 12
Kale	cool	Transplant (spring): January 24 · Sow (fall): September 28
Broccoli	cool	Transplant (spring): January 31
Carrots	cool	Sow (spring): January 24 · Sow (fall): September 28
Onions	cool	Transplant (spring): January 17
Potatoes	cool	Plant seed potatoes: January 31
Radishes	cool	Sow (spring): January 17 · Sow (fall): October 26

Dates are computed from Port Arthur's average frost dates using standard cool-/warm-season timing. They're a starting point — a cold spring, a warm microclimate, or a fast-maturing variety can shift them by a week or two.

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Gear that helps you plant on time

Some links below are Amazon affiliate links (tag theboringthin-20). If you buy through them we may earn a small commission at no extra cost to you — it keeps this almanac free. We only list generic, genuinely-useful categories.

Soil thermometer →Know when the ground is warm enough to sow — the honest signal, not the calendar.Seed-starting trays + dome →Start tomatoes & peppers indoors on the schedule below.Seedling heat mat →Warms the soil for faster, more even germination indoors.Floating row cover / frost cloth →Buys you 4–8°F to beat an early or late frost.Raised garden bed kit →Warms and drains faster in spring than in-ground soil.Garden gloves →Basic kit for transplant day.

Nearby cities in Texas

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Sources & method. Hardiness zone: 2023 USDA Plant Hardiness Zone Map (PRISM Climate Group, Oregon State University). Frost dates & growing season: NOAA/NCEI 1991–2020 U.S. Climate Normals, nearest station with published freeze normals — Port Arthur Se Tx Ap, TX, 6.8 mi (confidence: high). Monthly weather normals: Port Arthur Se Tx Ap, TX, 6.8 mi (confidence: high). ZIP centroid from U.S. Census 2023 ZCTA data. Frost dates are the 50%-probability date — half of years frost occurs outside the stated date. Nothing here is invented; where the nearest station is far, we say so. Last updated 2026-07-22.