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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 23°C (73°F). However, expect some variability, with temperatures dipping as low as 8°C (46°F) and soaring up to 37°C (99°F). This month also brings 129 mm (5.1 in) of precipitation over approximately 8 days, contributing to a relatively high average humidity of 71%.

September Temperature in Brownsville

In September in Brownsville, the average temperature is 23°C (73°F). Maximums can reach 37°C (99°F) and minimums can be as low as 8°C (46°F). This diverse temperature range makes Brownsville an ideal destination for travelers looking to enjoy both warm and cool experiences during their visit.

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 23°C (73°F), with highs reaching up to 37°C (99°F) and lows dropping to around 8°C (46°F).
JanFebMarAprMayJunJulAugSepOctNovDec384250576976807773624643
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 total precipitation amount is 129 mm (5.1 in) spread over a period of 8 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 129 mm (5.1 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec9917813615011914412011812912091131
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 71%. With an average temperature of 23°C (73°F), this humidity feels like a warm, sticky embrace, making outdoor exploration slightly uncomfortable but still manageable if you stay hydrated and plan for breaks in shaded areas.

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 71%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec87%86%86%82%83%83%80%74%71%78%88%88%
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 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For 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 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec36710101111109753
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 Weather3°C (38°F)99 mm (3.9 inches)87%moderate
February Weather6°C (43°F)177 mm (7.0 inches)86%high
March Weather10°C (50°F)136 mm (5.4 inches)86%high
April Weather14°C (58°F)150 mm (5.9 inches)82%very high
May Weather20°C (69°F)119 mm (4.7 inches)82%very high
June Weather24°C (76°F)144 mm (5.7 inches)83%extreme
July Weather27°C (80°F)120 mm (4.7 inches)80%extreme
August Weather25°C (78°F)118 mm (4.6 inches)74%very high
September Weather23°C (73°F)129 mm (5.1 inches)71%very high
October Weather16°C (62°F)120 mm (4.7 inches)78%high
November Weather8°C (47°F)91 mm (3.6 inches)88%moderate
December Weather6°C (43°F)131 mm (5.1 inches)88%moderate

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