September Weather in Port Isabel, United States

Last updated: June 24, 2025

In Port Isabel, United States, the average temperature in September hovers around 28°C (82°F), making it a warm destination for visitors. Expect minimum temperatures of 24°C (75°F) and maximums reaching 31°C (88°F). During this month, the region sees a precipitation amount of 136 mm (5.3 in) over approximately 17 days, coupled with an average humidity of 77%. Be prepared for a mix of warmth and occasional rainfall!

September Temperature in Port Isabel

In September in Port Isabel, the average temperature is 28°C (82°F). Maximums can reach 31°C (88°F) while minimums can drop to 24°C (75°F). This makes it a perfect destination for travelers seeking warm and pleasant weather.

September Weather in Port Isabel: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Port Isabel, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Port Isabel, September typically has an average temperature of 28°C (82°F), with highs reaching up to 31°C (88°F) and lows dropping to around 24°C (75°F).

Data source: Temperature data for Port Isabel generated using information from the Copernicus Climate Change Service.

September Precipitation in Port Isabel

In Port Isabel in September, the precipitation amount is 136 mm (5.3 in), occurring over a span of 17 days.

September Precipitation Trends in Port Isabel

The chart displays monthly precipitation patterns in Port Isabel, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Port Isabel, September typically receives around 136 mm (5.3 inches) of precipitation spread over approximately 17 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

September Humidity in Port Isabel

In Port Isabel in September humidity is 77%. With an average temperature of 28°C (82°F), this humidity feels like a warm, enveloping blanket that can make outdoor activities sticky and exhausting, but also offers a lush vibrancy to the landscape, perfect for enjoying leisurely strolls in the early morning or late afternoon.

September Average Humidity in Port Isabel

This chart illustrates the average monthly humidity levels in Port Isabel, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Port Isabel is approximately 77%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Port Isabel

In Port Isabel in September, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in Port Isabel.

Maximum UV Index Levels in Port Isabel for September

The chart shows the monthly maximum UV Index (UVI) for Port Isabel in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Port Isabel typically reaches 11, which falls under the extreme exposure category.

Data source: Port Isabel September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How September Weather in Port Isabel Compares to Other Months

Weather in Port Isabel varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Port Isabel, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Port Isabel, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	18°C (64°F)	47 mm (1.9 inches)	78%	high
February Weather	18°C (65°F)	36 mm (1.4 inches)	81%	very high
March Weather	20°C (69°F)	42 mm (1.6 inches)	81%	very high
April Weather	23°C (74°F)	26 mm (1.0 inches)	85%	extreme
May Weather	26°C (79°F)	68 mm (2.7 inches)	83%	extreme
June Weather	28°C (82°F)	87 mm (3.4 inches)	79%	extreme
July Weather	28°C (83°F)	125 mm (4.9 inches)	79%	extreme
August Weather	29°C (84°F)	32 mm (1.2 inches)	77%	extreme
September Weather	28°C (82°F)	136 mm (5.3 inches)	77%	extreme
October Weather	26°C (79°F)	94 mm (3.7 inches)	76%	very high
November Weather	22°C (72°F)	71 mm (2.8 inches)	79%	high
December Weather	19°C (67°F)	43 mm (1.7 inches)	79%	high