Port Arthur climate — normals and trends
Port Arthur (United States) has a humid subtropical climate (Cfa) under the Köppen-Geiger classification. Its mean annual temperature is 20.2 °C and it receives 1,251 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is July (27.8 °C on average) and the coldest is January (11.2 °C). Rainfall peaks in September.
Port Arthur averages 6 frost days, 94 hot days (≥ 30 °C) and 136 rainy days per year.
Port Arthur has warmed by +1.4 °C between 1940 and 2025, or +0.17 °C per decade. This trend is statistically significant.
The number of frost days there went from about 8 to 4 per year over the period.
The hottest day of the period reached 41.4 °C (on 27 August 2023) and the coldest -11.3 °C (on 2 February 1951).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
Port ArthurTexas
- coords
- 29.89°, -93.94°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
20.2°C
Average daily high
24.5°C
Average daily low
16.5°C
Annual rainfall
1,251mm
Sunshine / day
9.7h
Mean relative humidity
77%
Average peak wind
17.7km/h
Seasonal range
16.6°C
Frost days (< 0 °C)
6 d/yr
Hot days (≥ 30 °C)
94 d/yr
Rainy days (≥ 1 mm)
136 d/yr
Annual snowfall
0.8 cm
Average feels-like high
26.1 °C
Average feels-like low
16.9 °C
Average peak gust
34.7 km/h
Tropical nights (≥ 20 °C)
156 d/yr
Solar radiation
17.1 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.4 °C
since 1940
+0.2 °C per decade · r² = 0.38 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
41.4 °C
27 August 2023
Coldest day
-11.3 °C
2 February 1951
Wettest day
189 mm
13 September 2008
Windiest day
90.2 km/h
13 September 2008
Strongest gust
182.2 km/h
13 September 2008
Hottest feels-like
45.6 °C
24 August 2023
Coldest feels-like
-17.0 °C
23 December 1989
Snowiest day
14.4 cm
30 January 1949
Sunniest day
13.7 h
11 June 2020
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | 13.7 °C | -1.9 °C | 135 mm | +21 mm |
| Feb | 19.2 °C | +1.8 °C | 102 mm | +11 mm |
| Mar | 23.8 °C | +3.0 °C | 103 mm | +6 mm |
| Apr | 25.9 °C | +1.6 °C | 106 mm | -1 mm |
| May | 28.0 °C | +0.2 °C | 255 mm | +145 mm |
| Jun | 30.5 °C | 0.0 °C | 165 mm | +53 mm |
| Jul | 31.7 °C | +0.2 °C | 90 mm | -16 mm |
| Aug | 31.6 °C | -0.1 °C | 121 mm | +13 mm |
| Sep | 31.0 °C | +1.1 °C | 57 mm | -58 mm |
| Oct | 28.6 °C | +2.5 °C | 70 mm | -16 mm |
| Nov | 23.8 °C | +3.0 °C | 58 mm | -41 mm |
| Dec | 18.9 °C | +1.7 °C | 126 mm | +17 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Port Arthur?
Port Arthur has a humid subtropical climate (Köppen Cfa). Over 1940-2025, the average annual temperature is 20.2 °C and it receives 1,251 mm of precipitation per year.
What is the hottest day ever recorded in Port Arthur?
The hottest day measured in Port Arthur between 1940 and 2025 was 27 August 2023, reaching 41.4 °C.
What is the coldest day in Port Arthur?
The coldest day measured in Port Arthur between 1940 and 2025 was 2 February 1951, at -11.3 °C.
Does it snow in Port Arthur?
Almost never: Port Arthur sees virtually no snow, with about 6 frost days per year.
Has the climate of Port Arthur warmed?
Yes: Port Arthur warmed by +1.4 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Port Arthur?
The wettest day measured in Port Arthur between 1940 and 2025 was 13 September 2008, with 189 mm of rain in 24 hours.
What was the windiest day in Port Arthur?
The windiest day measured in Port Arthur between 1940 and 2025 was 13 September 2008, with winds reaching 90.2 km/h.
What is the warmest month in Port Arthur?
The warmest month in Port Arthur is July (27.8 °C on average); the coldest is January (11.2 °C).
How much does it rain in Port Arthur?
Port Arthur receives on average 1,251 mm of precipitation per year, spread over about 136 rainy days.
Is it sunny in Port Arthur?
Port Arthur gets on average 9.7 hours of sunshine per day, roughly 3,540 hours per year over 1940-2025.
What is the biggest single-day snowfall in Port Arthur?
The heaviest 24-hour snowfall measured in Port Arthur between 1940 and 2025 was 30 January 1949, with 14.4 cm.
Are there tropical nights in Port Arthur?
Yes: Port Arthur has on average 156 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Port Arthur?
In Port Arthur, between 1940 and 2025, the highest apparent temperature reached 45.6 °C on 24 August 2023, and the lowest was -17.0 °C on 23 December 1989.
Compare Port Arthur with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Port Arthur