September Weather in Stonington, United States

Last updated: June 24, 2025

In September, the average temperature in Stonington, United States is a pleasant 16°C (60°F). Expect a cool minimum of 9°C (48°F) and a comfortable maximum of 22°C (72°F). Be prepared for about 102 mm (4.0 in) of precipitation spread over 8 days, contributing to an average humidity level of 77%.

September Temperature in Stonington

In September in Stonington, the average temperature is 16°C (60°F), with maximums reaching 22°C (72°F) and minimums dropping as low as 9°C (48°F). This mild climate makes it an ideal time for outdoor activities and exploring the local sights.

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

The chart illustrates September temperature patterns in Stonington, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Stonington, September typically has an average temperature of 16°C (60°F), with highs reaching up to 22°C (72°F) and lows dropping to around 9°C (48°F).

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

September Precipitation in Stonington

In Stonington in September, the precipitation amount is 102 mm (4.0 in) over the course of 8 days.

September Precipitation Trends in Stonington

The chart displays monthly precipitation patterns in Stonington, 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 Stonington, September typically receives around 102 mm (4.0 inches) of precipitation spread over approximately 8 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 Stonington

In Stonington in September, humidity is 77%. With an average temperature of 16°C (60°F), this humidity feels like a moist blanket wrapping around you, making outdoor activities a bit uncomfortable and requiring frequent hydration as you soak in the vibrant local culture.

September Average Humidity in Stonington

This chart illustrates the average monthly humidity levels in Stonington, 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 Stonington is approximately 77%, 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 Stonington

In Stonington in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Stonington.

Maximum UV Index Levels in Stonington for September

The chart shows the monthly maximum UV Index (UVI) for Stonington 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 Stonington typically reaches 7, which falls under the high exposure category.

Data source: Stonington 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 Stonington Compares to Other Months

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

This table compares monthly weather conditions in Stonington, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-2°C (29°F)	108 mm (4.3 inches)	88%	low
February Weather	-1°C (30°F)	105 mm (4.1 inches)	88%	moderate
March Weather	0°C (33°F)	84 mm (3.3 inches)	85%	moderate
April Weather	5°C (41°F)	157 mm (6.2 inches)	81%	high
May Weather	9°C (49°F)	105 mm (4.1 inches)	76%	very high
June Weather	13°C (56°F)	87 mm (3.4 inches)	74%	very high
July Weather	16°C (62°F)	92 mm (3.6 inches)	74%	very high
August Weather	18°C (64°F)	86 mm (3.4 inches)	74%	very high
September Weather	16°C (60°F)	102 mm (4.0 inches)	77%	high
October Weather	12°C (54°F)	145 mm (5.7 inches)	82%	moderate
November Weather	6°C (43°F)	138 mm (5.4 inches)	85%	moderate
December Weather	1°C (34°F)	155 mm (6.1 inches)	84%	low