September Weather in McAllen, United States

Last updated: June 24, 2025

In McAllen, United States, the average temperature in September is a warm 29°C (84°F), with temperatures ranging from a refreshing 17°C (64°F) to a sizzling 41°C (106°F). During this month, expect approximately 96 mm (3.8 in) of precipitation spread over 11 days, creating a humidity level of around 73%. Whether you're basking in the sun or dodging a shower, September in McAllen offers a unique blend of tropical warmth and refreshing rain.

September Temperature in McAllen

In September in McAllen, the average temperature is 29°C (84°F), with maximums reaching up to 41°C (106°F) and minimums dipping as low as 17°C (64°F). This climate offers a warm and varied experience, making it ideal for travelers seeking both sunshine and cooler moments.

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

The chart illustrates September temperature patterns in McAllen, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In McAllen, September typically has an average temperature of 29°C (84°F), with highs reaching up to 41°C (106°F) and lows dropping to around 17°C (64°F).

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

September Precipitation in McAllen

In McAllen in September, the precipitation amount is 96 mm (3.8 in) spread over 11 days, resulting in a significant accumulation of rainfall.

September Precipitation Trends in McAllen

The chart displays monthly precipitation patterns in McAllen, 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 McAllen, September typically receives around 96 mm (3.8 inches) of precipitation spread over approximately 11 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 McAllen

In McAllen in September, humidity is 73%. With an average temperature of 29°C (84°F), this humidity feels like a warm blanket wrapped around you, making travel slightly uncomfortable as you sweat and seek shade, yet still inviting you to explore the vibrant local culture and activities.

September Average Humidity in McAllen

This chart illustrates the average monthly humidity levels in McAllen, 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 McAllen is approximately 73%, 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 McAllen

In McAllen 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 McAllen.

Maximum UV Index Levels in McAllen for September

The chart shows the monthly maximum UV Index (UVI) for McAllen 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 McAllen typically reaches 11, which falls under the extreme exposure category.

Data source: McAllen 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 McAllen Compares to Other Months

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

This table compares monthly weather conditions in McAllen, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	16°C (62°F)	20 mm (0.8 inches)	83%	high
February Weather	18°C (65°F)	21 mm (0.8 inches)	79%	very high
March Weather	22°C (72°F)	31 mm (1.2 inches)	76%	very high
April Weather	25°C (78°F)	31 mm (1.2 inches)	77%	extreme
May Weather	28°C (83°F)	87 mm (3.4 inches)	80%	extreme
June Weather	30°C (86°F)	81 mm (3.2 inches)	73%	extreme
July Weather	30°C (87°F)	100 mm (3.9 inches)	66%	extreme
August Weather	31°C (88°F)	22 mm (0.9 inches)	65%	extreme
September Weather	29°C (84°F)	96 mm (3.8 inches)	73%	extreme
October Weather	25°C (77°F)	51 mm (2.0 inches)	76%	very high
November Weather	20°C (69°F)	30 mm (1.2 inches)	80%	high
December Weather	18°C (64°F)	21 mm (0.8 inches)	86%	high