September Weather in Brownsville, United States

Last updated: June 24, 2025

In Brownsville, United States, the average temperature in September is a comfortable 18°C (64°F). However, temperatures can vary widely, with minimums dipping to 5°C (41°F) and soaring to a maximum of 36°C (97°F). Expect a moderate level of precipitation, averaging 62 mm (2.5 in) over approximately 7 days. With an average humidity of 71%, you’ll want to be prepared for a blend of warmth and moisture during your stay!

September Temperature in Brownsville

In September in Brownsville, the average temperature is 18°C (64°F). The maximum can reach 36°C (97°F) and the minimum can be as low as 5°C (41°F). It's a great time to visit for those who enjoy a range of temperatures and 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 18°C (64°F), with highs reaching up to 36°C (97°F) and lows dropping to around 5°C (41°F).

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

September Precipitation in Brownsville

In Brownsville in September, the precipitation amount is 62 mm (2.5 in) over a period of 7 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 62 mm (2.5 inches) of precipitation spread over approximately 7 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

September Humidity in Brownsville

In Brownsville in September, humidity is 71%. With an average temperature of 18°C (64°F), this humidity feels like a warm embrace, making traveling a bit sticky but still pleasant as the warmth envelops you, urging you to explore the vibrant surroundings while staying hydrated.

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.

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 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to 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 8, which falls under the very high exposure category.

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.
	Temperature	Precipitation	Humidity	UV
January Weather	6°C (42°F)	144 mm (5.7 inches)	85%	low
February Weather	5°C (42°F)	181 mm (7.1 inches)	84%	moderate
March Weather	8°C (46°F)	125 mm (4.9 inches)	85%	high
April Weather	10°C (51°F)	113 mm (4.4 inches)	83%	high
May Weather	14°C (57°F)	57 mm (2.3 inches)	83%	very high
June Weather	18°C (64°F)	38 mm (1.5 inches)	83%	very high
July Weather	21°C (70°F)	2 mm (0.1 inches)	82%	very high
August Weather	21°C (71°F)	5 mm (0.2 inches)	74%	very high
September Weather	18°C (64°F)	62 mm (2.5 inches)	71%	very high
October Weather	12°C (54°F)	88 mm (3.5 inches)	81%	moderate
November Weather	8°C (47°F)	130 mm (5.1 inches)	87%	moderate
December Weather	5°C (42°F)	182 mm (7.2 inches)	87%	low