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September Weather in Brownsville, United States

Last updated: June 24, 2025

In September, the average temperature in Brownsville, United States hovers around 18°C (64°F). Temperatures can vary significantly, with a minimum of 1°C (35°F) and a maximum reaching 33°C (92°F). Be prepared for some rain, as 89 mm (3.5 in) of precipitation is expected over the course of 10 days, complemented by an average humidity level of 79%.

September Temperature in Brownsville

In September in Brownsville, the average temperature is 18°C (64°F). The maximum can reach 33°C (92°F), while the minimum can drop as low as 1°C (35°F). This makes it an ideal time for outdoor activities and exploring the local attractions, but be sure to pack for both warm days and cool nights.

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 18°C (64°F), with highs reaching up to 33°C (92°F) and lows dropping to around 1°C (35°F).
JanFebMarAprMayJunJulAugSepOctNovDec212234445869737064503628
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 89 mm (3.5 in) over a period of 10 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 89 mm (3.5 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec50495610511910710194891124445
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 79%. With an average temperature of 18°C (64°F), this humidity feels like a warm, sticky embrace that can make outdoor activities more challenging but also creates a lush, vibrant atmosphere that's perfect for exploring local culture and scenery.

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 79%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%85%85%85%78%80%78%76%79%83%88%82%
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 is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, 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 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec24589101097532
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 Weather-6°C (21°F)50 mm (2.0 inches)85%low
February Weather-6°C (22°F)49 mm (1.9 inches)85%moderate
March Weather1°C (35°F)56 mm (2.2 inches)85%moderate
April Weather7°C (45°F)105 mm (4.1 inches)85%very high
May Weather14°C (58°F)119 mm (4.7 inches)78%very high
June Weather20°C (69°F)107 mm (4.2 inches)80%very high
July Weather23°C (73°F)101 mm (4.0 inches)78%very high
August Weather21°C (70°F)94 mm (3.7 inches)76%very high
September Weather18°C (64°F)89 mm (3.5 inches)79%high
October Weather10°C (51°F)112 mm (4.4 inches)83%moderate
November Weather2°C (36°F)44 mm (1.7 inches)88%moderate
December Weather-2°C (29°F)45 mm (1.8 inches)81%low

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