September Weather in Acton, United States

Last updated: June 24, 2025

In September, the average temperature in Acton, United States hovers around 23°C (73°F). Expect a minimum of 9°C (48°F) and a maximum soaring to 42°C (107°F). With an average humidity of 48%, the area experiences a modest precipitation of 6 mm (0.3 in) over just 1 day. Stay prepared for a range of weather conditions!

September Temperature in Acton

In September in Acton, the average temperature is 23°C (73°F). Maximums can reach 42°C (107°F) and minimums can be as low as 9°C (48°F). Be prepared for a wide range of temperatures to fully enjoy your travel experience.

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

The chart illustrates September temperature patterns in Acton, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Acton, September typically has an average temperature of 23°C (73°F), with highs reaching up to 42°C (107°F) and lows dropping to around 9°C (48°F).

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

September Precipitation in Acton

In Acton in September, the precipitation amount is 6 mm (0.3 in) over the course of 1 day.

September Precipitation Trends in Acton

The chart displays monthly precipitation patterns in Acton, 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 Acton, September typically receives around 6 mm (0.3 inches) of precipitation spread over approximately 1 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 Acton

In Acton in September humidity is 48%. With an average temperature of 23°C (73°F), this humidity feels like a pleasant embrace, making it comfortable for traveling while allowing you to enjoy outdoor activities without feeling overly sticky or weighed down.

September Average Humidity in Acton

This chart illustrates the average monthly humidity levels in Acton, 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 Acton is approximately 48%, 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 Acton

In Acton 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 Acton.

Maximum UV Index Levels in Acton for September

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

Data source: Acton 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 Acton Compares to Other Months

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

This table compares monthly weather conditions in Acton, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	9°C (49°F)	58 mm (2.3 inches)	78%	moderate
February Weather	10°C (50°F)	53 mm (2.1 inches)	82%	high
March Weather	11°C (53°F)	73 mm (2.9 inches)	75%	very high
April Weather	15°C (60°F)	22 mm (0.9 inches)	68%	very high
May Weather	17°C (64°F)	13 mm (0.5 inches)	57%	extreme
June Weather	22°C (72°F)	3 mm (0.1 inches)	52%	extreme
July Weather	25°C (78°F)	4 mm (0.2 inches)	46%	extreme
August Weather	25°C (78°F)	6 mm (0.2 inches)	39%	extreme
September Weather	23°C (73°F)	6 mm (0.3 inches)	48%	very high
October Weather	18°C (65°F)	7 mm (0.3 inches)	59%	high
November Weather	14°C (57°F)	20 mm (0.8 inches)	72%	moderate
December Weather	9°C (49°F)	65 mm (2.6 inches)	76%	moderate