September Weather in Stonington, United States

Last updated: June 24, 2025

In September, the average temperature in Stonington, United States hovers around 22°C (71°F). Expect a minimum of 6°C (42°F) and a maximum of 35°C (95°F) during this time. Rainfall is likely, with an average precipitation of 61 mm (2.4 in) spread over about 7 days. Additionally, the average humidity is around 79%, adding to the overall warmth.

September Temperature in Stonington

In September in Stonington, the average temperature is 22°C (71°F). Maximum temperatures can reach 35°C (95°F), while minimum temperatures can drop as low as 6°C (42°F). Overall, it's a great time for travelers to enjoy mild weather and a range of outdoor activities.

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 22°C (71°F), with highs reaching up to 35°C (95°F) and lows dropping to around 6°C (42°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 61 mm (2.4 in) over the course of 7 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 61 mm (2.4 inches) of precipitation spread over approximately 7 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 Stonington

In Stonington in September humidity is 79%. With an average temperature of 22°C (71°F), this humidity feels like a warm, sticky embrace that can make any outdoor adventure quite challenging for traveling; it's advisable to stay hydrated and take breaks in the shade to fully enjoy the sights.

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 79%, 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 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 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 8, which falls under the very 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 (30°F)	72 mm (2.8 inches)	84%	moderate
February Weather	0°C (32°F)	74 mm (2.9 inches)	82%	moderate
March Weather	6°C (44°F)	130 mm (5.1 inches)	84%	high
April Weather	11°C (53°F)	130 mm (5.1 inches)	83%	very high
May Weather	19°C (66°F)	145 mm (5.7 inches)	80%	very high
June Weather	24°C (75°F)	111 mm (4.4 inches)	83%	extreme
July Weather	25°C (78°F)	115 mm (4.5 inches)	82%	extreme
August Weather	23°C (74°F)	91 mm (3.6 inches)	82%	very high
September Weather	22°C (71°F)	61 mm (2.4 inches)	79%	very high
October Weather	14°C (58°F)	109 mm (4.3 inches)	79%	high
November Weather	5°C (42°F)	72 mm (2.8 inches)	88%	moderate
December Weather	2°C (37°F)	51 mm (2.0 inches)	87%	moderate