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September Weather in Brownsville, United States

Last updated: June 24, 2025

In September, the average temperature in Brownsville, United States is a warm 28°C (83°F). Expect lows of 18°C (65°F) and highs reaching up to 36°C (97°F). With an average humidity of 75%, you might feel the heat, especially since 116 mm (4.6 in) of precipitation can occur over 17 days. Prepare for a tropical experience!

September Temperature in Brownsville

In September in Brownsville, the average temperature is 28°C (83°F). Maximums can reach 36°C (97°F), while minimums can drop as low as 18°C (65°F). It's an ideal time for travelers seeking warm weather and pleasant conditions for outdoor activities.

September Weather in Brownsville: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Brownsville, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Brownsville, September typically has an average temperature of 28°C (83°F), with highs reaching up to 36°C (97°F) and lows dropping to around 18°C (65°F).
JanFebMarAprMayJunJulAugSepOctNovDec626571768184858682777065
Data source: Temperature data for Brownsville generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Brownsville

In Brownsville in September, the precipitation amount is 116 mm (4.6 in) spread over 17 days.

September Precipitation Trends in Brownsville

The chart displays monthly precipitation patterns in Brownsville, 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 Brownsville, September typically receives around 116 mm (4.6 inches) of precipitation spread over approximately 17 days.
JanFebMarAprMayJunJulAugSepOctNovDec31223927769211936116553526
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Brownsville

In Brownsville in September humidity is 75%. With an average temperature of 28°C (83°F), this humidity feels like a warm blanket enveloping you, making outdoor activities feel particularly heavy, and prompting frequent breaks in the shade to stay comfortable while traveling.

September Average Humidity in Brownsville

This chart illustrates the average monthly humidity levels in Brownsville, 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 Brownsville is approximately 75%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%83%78%81%82%74%68%67%75%78%83%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Brownsville

In Brownsville 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 Brownsville.

Maximum UV Index Levels in Brownsville for September

The chart shows the monthly maximum UV Index (UVI) for Brownsville 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 Brownsville typically reaches 11, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec69101112121212111076
Data source: Brownsville 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 Brownsville Compares to Other Months

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

This table compares monthly weather conditions in Brownsville, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather17°C (63°F)31 mm (1.2 inches)84%high
February Weather18°C (65°F)22 mm (0.9 inches)83%very high
March Weather22°C (71°F)39 mm (1.5 inches)78%very high
April Weather24°C (76°F)27 mm (1.1 inches)81%extreme
May Weather27°C (81°F)76 mm (3.0 inches)82%extreme
June Weather29°C (84°F)92 mm (3.6 inches)74%extreme
July Weather29°C (85°F)119 mm (4.7 inches)68%extreme
August Weather30°C (86°F)36 mm (1.4 inches)67%extreme
September Weather28°C (83°F)116 mm (4.6 inches)75%extreme
October Weather25°C (77°F)55 mm (2.2 inches)78%very high
November Weather21°C (70°F)35 mm (1.4 inches)83%high
December Weather18°C (65°F)26 mm (1.0 inches)86%high

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