September Weather in Austin, United States

Last updated: June 24, 2025

In Austin, United States, the average temperature in September hovers around 18°C (64°F). Daily temperatures can range from a chilly minimum of 2°C (36°F) to a scorching maximum of 33°C (91°F). Expect about 121 mm (4.8 in) of precipitation spread over 9 days, contributing to an average humidity of 75%.

September Temperature in Austin

In September in Austin, the average temperature is 18°C (64°F). Maximums can reach 33°C (91°F), and minimums can be as low as 2°C (36°F). This makes Austin a great destination for travelers looking to experience a range of temperatures, from warm days to cooler nights.

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

The chart illustrates September temperature patterns in Austin, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Austin, September typically has an average temperature of 18°C (64°F), with highs reaching up to 33°C (91°F) and lows dropping to around 2°C (36°F).

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

September Precipitation in Austin

In Austin in September, the precipitation amount is 121 mm (4.8 in) over the course of 9 days.

September Precipitation Trends in Austin

The chart displays monthly precipitation patterns in Austin, 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 Austin, September typically receives around 121 mm (4.8 inches) of precipitation spread over approximately 9 days.

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

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Millimeters (mm) Inches (in)

September Humidity in Austin

In Austin in September, humidity is 75%. With an average temperature of 18°C (64°F), this humidity feels like a warm blanket enveloping you, making your travels a bit sticky and requiring frequent breaks in the shade to stay comfortable.

September Average Humidity in Austin

This chart illustrates the average monthly humidity levels in Austin, 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 Austin is approximately 75%, 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 Austin

In Austin 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 Austin.

Maximum UV Index Levels in Austin for September

The chart shows the monthly maximum UV Index (UVI) for Austin 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 Austin typically reaches 8, which falls under the very high exposure category.

Data source: Austin 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 Austin Compares to Other Months

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

This table compares monthly weather conditions in Austin, 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 (17°F)	36 mm (1.4 inches)	82%	moderate
February Weather	-9°C (17°F)	46 mm (1.8 inches)	84%	moderate
March Weather	1°C (34°F)	67 mm (2.6 inches)	80%	moderate
April Weather	7°C (44°F)	85 mm (3.3 inches)	81%	very high
May Weather	15°C (59°F)	148 mm (5.8 inches)	74%	very high
June Weather	22°C (71°F)	134 mm (5.3 inches)	80%	very high
July Weather	23°C (73°F)	98 mm (3.9 inches)	80%	very high
August Weather	21°C (70°F)	107 mm (4.2 inches)	77%	very high
September Weather	18°C (64°F)	121 mm (4.8 inches)	75%	very high
October Weather	9°C (49°F)	104 mm (4.1 inches)	80%	moderate
November Weather	1°C (34°F)	45 mm (1.8 inches)	87%	moderate
December Weather	-4°C (25°F)	37 mm (1.5 inches)	83%	moderate