September Weather in Marietta, United States

Last updated: June 24, 2025

In September, the average temperature in Marietta, United States hovers around 21°C (70°F), offering a pleasant climate. Expect minimum temperatures to drop to 5°C (42°F), while the mercury can rise as high as 34°C (93°F). During this month, precipitation levels reach 108 mm (4.2 in) over approximately 9 days, contributing to an average humidity of 75%. Stay prepared for captivating weather contrasts!

September Temperature in Marietta

In September in Marietta, the average temperature is 21°C (70°F), with maximums reaching 34°C (93°F) and minimums dropping as low as 5°C (42°F). This range makes Marietta a perfect destination for travelers seeking both warm days and cooler evenings.

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

The chart illustrates September temperature patterns in Marietta, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Marietta, September typically has an average temperature of 21°C (70°F), with highs reaching up to 34°C (93°F) and lows dropping to around 5°C (42°F).

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

September Precipitation in Marietta

In Marietta in September, the precipitation amount is 108 mm (4.2 in) spread over 9 days.

September Precipitation Trends in Marietta

The chart displays monthly precipitation patterns in Marietta, 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 Marietta, September typically receives around 108 mm (4.2 inches) of precipitation spread over approximately 9 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 Marietta

In Marietta in September, humidity is 75%. With an average temperature of 21°C (70°F), this humidity feels like a warm, enveloping blanket that makes exploring the area feel slightly sticky, requiring travelers to stay hydrated and take occasional breaks in the shade to fully enjoy their adventures.

September Average Humidity in Marietta

This chart illustrates the average monthly humidity levels in Marietta, 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 Marietta 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 Marietta

In Marietta 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 Marietta.

Maximum UV Index Levels in Marietta for September

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

Data source: Marietta 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 Marietta Compares to Other Months

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

This table compares monthly weather conditions in Marietta, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	1°C (35°F)	60 mm (2.4 inches)	84%	moderate
February Weather	3°C (38°F)	101 mm (4.0 inches)	83%	moderate
March Weather	6°C (44°F)	99 mm (3.9 inches)	83%	high
April Weather	12°C (54°F)	98 mm (3.9 inches)	81%	very high
May Weather	18°C (64°F)	125 mm (4.9 inches)	78%	very high
June Weather	23°C (73°F)	97 mm (3.8 inches)	79%	very high
July Weather	26°C (79°F)	130 mm (5.1 inches)	74%	very high
August Weather	24°C (76°F)	130 mm (5.1 inches)	72%	very high
September Weather	21°C (70°F)	108 mm (4.2 inches)	75%	very high
October Weather	16°C (60°F)	101 mm (4.0 inches)	81%	high
November Weather	7°C (45°F)	88 mm (3.5 inches)	85%	moderate
December Weather	4°C (39°F)	93 mm (3.7 inches)	84%	low