Photo: lfwlfw / Bevo at English Wikipedia · Public domainHardly any U.S. towns see softer January nights than Port Isabel
Midsummer highs settle at about 92°. Rain follows the seasons: September brings about 4.8 times as much as February. Its yearly precipitation falls short of 87% of U.S. towns. Long walks are most pleasant from November to April, when afternoons reach 70–82°.
A year in Port Isabel at a glance
Each month’s typical high and low, and what it brings.
What stands out about Port Isabel’s climate
Compared with towns across the U.S., with Port Isabel’s place in Texas beside it.
What a year in Port Isabel feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
Frost is rare
Frost and day counts come from NOAA’s station at Port Isabel, TX, 2.0 miles from the town’s center, at about the same height.
The 2023 USDA map puts Port Isabel’s center in zone 10b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 35°. Plant labels use the zone; frost dates tell you when to plant.
90° days by month
Average days at 90° or more
About 26 inches of rain a year
September is the wettest month and February the driest. Rain falls on about 67 days a year. Snow is rare: about 0.2" in a normal year at Port Isabel, TX, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Port Isabel
13% of the work is heating, so air conditioning is the bigger bill. No month averages under 55°.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Port Isabel, TX.
Living with Port Isabel’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
Zone 10b. Frost comes about 1 winter in 3, so tender plants can often stay out through winter.
Months with highs of 62–84° and lows of 40° or more: January, February, March, April, November and December. 29 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Port Isabel from natural hazards, hurricanes are the largest share (66%); heat waves, cold waves, winter storms and ice storms together are 11%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Port Isabel and its neighbors
Brownsville the hottest July afternoons (94°, 3° warmer). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Port Isabel’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Port Isabel, TX | 52° | 92° | 26" | 0.2" |
| La Cañada Flintridge, CA | 45° | 90° | 22" | 0.0" |
| Waihee-Waiehu, HI | 64° | 89° | 16" | 0.0" |
| Marathon, FL | 64° | 90° | 42" | 0.0" |
| Grants Pass, OR | 34° | 90° | 33" | 0.9" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Port Isabel averaged 1.2° warmer than the 1900s. The biggest change is in February (+2.3°).
A smaller shift than in 60% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Port Isabel compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Port Isabel’s place among Texas’.
Port Isabel weather by month
Highs, lows and precipitation from NOAA’s grid at Port Isabel’s center; snow, wet days and snow on the ground from Port Isabel, TX. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 70° | 52° | 1.2" | 0.0" | 8 | 0 | 55° – 67° |
| February | 73° | 57° | 1.1" | 0.0" | 5 | 0 | 58° – 73° |
| March | 77° | 62° | 1.4" | 0.0" | 5 | 0 | 63° – 76° |
| April | 82° | 67° | 1.4" | 0.0" | 4 | 0 | 70° – 79° |
| May | 87° | 73° | 2.2" | 0.0" | 4 | 0 | 76° – 83° |
| June | 91° | 77° | 3.0" | 0.0" | 4 | 0 | 81° – 87° |
| July | 92° | 77° | 1.8" | 0.0" | 4 | 0 | 82° – 87° |
| August | 93° | 77° | 2.0" | 0.0" | 4 | 0 | 83° – 88° |
| September | 90° | 74° | 5.4" | 0.0" | 8 | 0 | 79° – 85° |
| October | 85° | 68° | 3.3" | 0.0" | 7 | 0 | 74° – 80° |
| November | 78° | 61° | 1.9" | 0.0" | 6 | 0 | 64° – 75° |
| December | 72° | 54° | 1.4" | 0.2" | 8 | 0 | 57° – 67° |
| Year | 82° | 67° | 26.1" | 0.2" | 67 | 0 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 58° to 73°. June is the most reliable, staying within 5°.
Where Port Isabel’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Port Isabel’s center.
- Snow: Port Isabel, TX (NOAA station in town).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Port Isabel, TX, 2.0 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Port Isabel’s climate
What is the weather like in Port Isabel?
A typical July afternoon reaches 92°, a January night drops to 52°, and snow is almost unheard of. Milder January nights than 98% of U.S. towns; hotter July afternoons than 85% of U.S. towns.
How cold does it get in Port Isabel in winter?
January nights average 52°. A night at 32° or below comes in only some winters (0.8 a year on average). In the coldest January of the last 30 years the month averaged 55°.
How much snow does Port Isabel get?
About 0.2 inches in a normal winter at Port Isabel, TX, so most winters see none.
How hot does it get in Port Isabel?
July, with a typical high of 92° and a low of 77°. About 95 days a year reach 90° (Port Isabel, TX).
When is the first and last frost in Port Isabel?
Most years have no frost at all: a 32° night comes in about 34% of winters at Port Isabel, TX, usually in December or January.
What growing zone is Port Isabel in?
Zone 10b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 35°.
What is the best time of year to visit Port Isabel?
By one simple rule (highs of 62–84° and lows of 40° or more), January, February, March, April, November and December. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Port Isabel getting warmer?
Yes: 1991–2020 averaged 1.2° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 60% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Port Isabel.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.