Port Mansfield, Texas climate: Normal weather by month, frost dates and records
Port Mansfield's normal year runs from 50°F January nights to 92°F August afternoons, with 25.3 inches of precipitation and less than an inch of snow (0.1 in) a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 23.0°C, January lows of 10°C, August highs of 33°C, 641 mm of precipitation a year.
- NOAA stationPort Mansfield
- Station IDUSC00417184
- Location26.56°N 97.43°W
- Elevation9 ft (3 m)
- Population (census place)157
On October 23, the normal high in Port Mansfield is 83°F and the normal low 66°F, and the chance of measurable rain or snow is 18%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Port Mansfield.
- Jan 68° 50°
- Feb 71° 55°
- Mar 76° 61°
- Apr 81° 67°
- May 85° 73°
- Jun 90° 77°
- Jul 91° 78°
- Aug 92° 78°
- Sep 89° 74°
- Oct 84° 68°
- Nov 76° 60°
- Dec 70° 52°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Port Mansfield each month?
August is the warmest month, with normal highs of 92°F; January the coldest, with normal lows of 50°F. The most precipitation falls in September (5.37 in), the least in January (1.13 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 68°F | 50°F | 59.0°F | 1.13 | 6 | <1 | 1 | 10 h 40 min |
| February | 71°F | 55°F | 62.8°F | 1.75 | 5 | <1 | 1 | 11 h 10 min |
| March | 76°F | 61°F | 68.0°F | 1.33 | 4 | <1 | <1 | 12 h |
| April | 81°F | 67°F | 73.6°F | 1.41 | 4 | 1 | <1 | 12 h 50 min |
| May | 85°F | 73°F | 79.0°F | 2.39 | 4 | 2 | <1 | 13 h 30 min |
| June | 90°F | 77°F | 83.1°F | 2.00 | 4 | 11 | <1 | 13 h 50 min |
| July | 91°F | 78°F | 84.1°F | 2.39 | 4 | 17 | <1 | 13 h 40 min |
| August | 92°F | 78°F | 84.7°F | 1.15 | 3 | 22 | <1 | 13 h 10 min |
| September | 89°F | 74°F | 81.1°F | 5.37 | 9 | 10 | <1 | 12 h 20 min |
| October | 84°F | 68°F | 76.0°F | 3.10 | 6 | 3 | <1 | 11 h 30 min |
| November | 76°F | 60°F | 68.0°F | 1.98 | 5 | <1 | <1 | 10 h 50 min |
| December | 70°F | 52°F | 61.2°F | 1.25 | 6 | <1 | <1 | 10 h 30 min |
| Year (annual) | 81°F | 66°F | 73.4°F | 25.25 | 59 | 68 | 2 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 20°C | 10°C | 15.0°C | 29 mm |
| February | 22°C | 13°C | 17.1°C | 44 mm |
| March | 24°C | 16°C | 20.0°C | 34 mm |
| April | 27°C | 19°C | 23.1°C | 36 mm |
| May | 30°C | 23°C | 26.1°C | 61 mm |
| June | 32°C | 25°C | 28.4°C | 51 mm |
| July | 33°C | 25°C | 28.9°C | 61 mm |
| August | 33°C | 25°C | 29.3°C | 29 mm |
| September | 31°C | 23°C | 27.3°C | 136 mm |
| October | 29°C | 20°C | 24.4°C | 79 mm |
| November | 25°C | 15°C | 20.0°C | 50 mm |
| December | 21°C | 11°C | 16.2°C | 32 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00417184; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Port Mansfield?
Normal highs sit between 65°F and 85°F in January, February, March, April, October, November and December. Of those, April has the fewest days with rain (4).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00417184.
When is the last frost in Port Mansfield?
In Port Mansfield, the last spring frost (32°F) comes after January 12 in half of years and after February 19 in one year in ten; the first autumn frost comes before January 1 in half of years and before December 5 in one year in ten. A night at 32°F or colder comes at all in 56% of years here (NOAA).
- Last spring frost, half of years after
- January 121 year in 10 after February 19; 9 in 10 after December 15
- First autumn frost, half of years before
- January 11 year in 10 before December 5; 9 in 10 before February 5
NOAA puts the median frost-free season at 362 days, and the season without a hard freeze (28°F) at 365 days.
A hard freeze (28°F) comes after January 7 in half of springs and before January 5 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Port Mansfield in zone 10a in ZIP code 78598.
Frost dates for every NOAA station in Texas · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00417184; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Port Mansfield?
In a normal year in Port Mansfield, 68 days a year reach 90°F (1 of them 100°F or more), 2 nights fall to 32°F or colder and 59 days bring measurable precipitation.
- Days at 90°F or more
- 68a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 2a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 59a normal year
Source: NOAA NCEI 1991-2020 annual normals, station USC00417184.
How sunny is Port Mansfield?
Over a year 79% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Port Mansfield, 4.8 kWh per square metre a day. August is the sunniest month (87%) and December the cloudiest (68%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 69% | 3.1 |
| February | 70% | 3.7 |
| March | 73% | 4.6 |
| April | 77% | 5.4 |
| May | 82% | 6.0 |
| June | 86% | 6.5 |
| July | 86% | 6.5 |
| August | 87% | 6.2 |
| September | 80% | 5.2 |
| October | 83% | 4.6 |
| November | 76% | 3.5 |
| December | 68% | 2.8 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Port Mansfield need?
A normal year in Port Mansfield brings 674 heating degree days, 87% fewer than the median U.S. place (5,373), and 3,755 cooling degree days, 4.1 times the median (908). No month reaches 300 heating degree days. For gardens and crops, NOAA counts 8,611 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 223 | 37 |
| February | 128 | 65 |
| March | 55 | 150 |
| April | 10 | 270 |
| May | 1 | 435 |
| June | 0 | 543 |
| July | 0 | 592 |
| August | 0 | 609 |
| September | 0 | 482 |
| October | 7 | 350 |
| November | 70 | 160 |
| December | 180 | 64 |
| Year (annual) | 674 | 3,755 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00417184. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Port Mansfield been warmer than normal lately?
2025 averaged 74.6°F, 1.2°F above the 1991-2020 normal of 73.4°F.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2025 | 74.6°F | +1.2°F | 43.90 |
Source: observed years: ACIS, station USC00417184. A year counts only with all twelve months complete.
How does Port Mansfield's climate compare?
Port Mansfield is warmer than 305 of the other 320 places with their own NOAA record in Texas, and wetter than 113. Across the 7,247 U.S. stations with normals, its annual mean of 73.4°F is warmer than 98%.
In the Köppen classification computed from these normals, Port Mansfield is Cfa: temperate, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Questions about Port Mansfield's climate
What is the coldest month in Port Mansfield?
January, with a normal high of 68°F and a normal low of 50°F. The warmest is August (92°F by day, 78°F at night).
Does it snow in Port Mansfield?
Rarely: NOAA's normal is 0.1 inch a year.
What is the rainiest month in Port Mansfield?
September, with 5.37 in of precipitation in a normal year; the driest is January with 1.13 in.
What plant hardiness zone is Port Mansfield in?
The USDA's 2023 map puts Port Mansfield in zone 10a in ZIP code 78598.
How late can frost come in Port Mansfield?
In half of years the last 32°F night comes after January 12; in one year in ten it comes after February 19. Waiting until February 19 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Texas climateThe statewide normals and every place in the state
- Raymondville, TX23 miles from this station, 74.4°F a year
- Armstrong (4 mi SE), TX26 miles from this station, 73.2°F a year
- Harlingen, TX27 miles from this station, 74.9°F a year
- Port Isabel, TX27 miles from this station, 74.8°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made