September Weather in Allen, United States

Last updated: June 24, 2025

In Allen, United States, the average temperature for September is a pleasant 26°C (79°F). However, you can expect a range, with minimums dipping to 10°C (51°F) and maximums soaring up to 37°C (99°F). During this month, precipitation averages 92 mm (3.6 in) over about 7 days, and the average humidity hovers around 65%, creating a warm yet refreshing atmosphere.

September Temperature in Allen

In September in Allen, the average temperature is 26°C (79°F). Maximum temperatures can reach 37°C (99°F), while minimums can dip as low as 10°C (51°F). It's a great time to explore Allen with a mix of warm days and cooler evenings.

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

The chart illustrates September temperature patterns in Allen, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Allen, September typically has an average temperature of 26°C (79°F), with highs reaching up to 37°C (99°F) and lows dropping to around 10°C (51°F).

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

September Precipitation in Allen

In Allen in September, the precipitation amount is 92 mm (3.6 in) over the course of 7 days.

September Precipitation Trends in Allen

The chart displays monthly precipitation patterns in Allen, 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 Allen, September typically receives around 92 mm (3.6 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 Allen

In Allen in September, humidity is 65%. With an average temperature of 26°C (79°F), this humidity feels like a warm, enveloping blanket, making travel quite sticky and uncomfortable.

September Average Humidity in Allen

This chart illustrates the average monthly humidity levels in Allen, 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 Allen is approximately 65%, 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 Allen

In Allen in September, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in Allen.

Maximum UV Index Levels in Allen for September

The chart shows the monthly maximum UV Index (UVI) for Allen 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 Allen typically reaches 10, which falls under the very high exposure category.

Data source: Allen 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 Allen Compares to Other Months

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

This table compares monthly weather conditions in Allen, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	8°C (47°F)	59 mm (2.3 inches)	80%	moderate
February Weather	9°C (49°F)	102 mm (4.0 inches)	79%	high
March Weather	15°C (60°F)	120 mm (4.7 inches)	78%	very high
April Weather	18°C (65°F)	121 mm (4.8 inches)	78%	very high
May Weather	23°C (74°F)	177 mm (7.0 inches)	81%	extreme
June Weather	27°C (81°F)	86 mm (3.4 inches)	78%	extreme
July Weather	29°C (85°F)	50 mm (2.0 inches)	73%	extreme
August Weather	29°C (85°F)	98 mm (3.9 inches)	66%	extreme
September Weather	26°C (79°F)	92 mm (3.6 inches)	65%	very high
October Weather	20°C (68°F)	146 mm (5.8 inches)	72%	very high
November Weather	13°C (56°F)	58 mm (2.3 inches)	82%	high
December Weather	11°C (51°F)	67 mm (2.6 inches)	87%	moderate