September Weather in Plymouth, United States

Last updated: June 24, 2025

In September, the average temperature in Plymouth, United States hovers around 16°C (62°F). During this time, temperatures can fluctuate from a chilly 0°C (33°F) to a warm 32°C (89°F). Expect about 70 mm (2.8 in) of precipitation over roughly 7 days, accompanied by an average humidity level of 77%, creating a refreshing atmosphere perfect for exploring.

September Temperature in Plymouth

In September in Plymouth, the average temperature is 16°C (62°F), with maximums reaching up to 32°C (89°F) and minimums dropping as low as 0°C (33°F). This varied climate makes it essential for travelers to pack for both warm and cold conditions.

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

The chart illustrates September temperature patterns in Plymouth, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Plymouth, September typically has an average temperature of 16°C (62°F), with highs reaching up to 32°C (89°F) and lows dropping to around 0°C (33°F).

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

September Precipitation in Plymouth

In Plymouth in September, the precipitation amount is 70 mm (2.8 in) over a span of 7 days.

September Precipitation Trends in Plymouth

The chart displays monthly precipitation patterns in Plymouth, 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 Plymouth, September typically receives around 70 mm (2.8 inches) of precipitation spread over approximately 7 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 Plymouth

In Plymouth in September, humidity is 77%. With an average temperature of 16°C (62°F), this humidity feels like a warm, enveloping blanket that can make outdoor activities feel heavy and draining, so travelers may want to plan for breaks in shaded areas and stay hydrated.

September Average Humidity in Plymouth

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

In Plymouth 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 Plymouth.

Maximum UV Index Levels in Plymouth for September

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

Data source: Plymouth 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 Plymouth Compares to Other Months

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

This table compares monthly weather conditions in Plymouth, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-6°C (21°F)	86 mm (3.4 inches)	88%	low
February Weather	-5°C (24°F)	81 mm (3.2 inches)	88%	moderate
March Weather	-1°C (31°F)	71 mm (2.8 inches)	85%	moderate
April Weather	6°C (43°F)	121 mm (4.8 inches)	81%	high
May Weather	12°C (54°F)	91 mm (3.6 inches)	76%	very high
June Weather	18°C (64°F)	75 mm (2.9 inches)	74%	very high
July Weather	21°C (70°F)	103 mm (4.1 inches)	74%	very high
August Weather	20°C (69°F)	73 mm (2.9 inches)	74%	very high
September Weather	16°C (62°F)	70 mm (2.8 inches)	77%	high
October Weather	10°C (50°F)	119 mm (4.7 inches)	82%	moderate
November Weather	2°C (36°F)	111 mm (4.4 inches)	85%	moderate
December Weather	-4°C (26°F)	113 mm (4.5 inches)	84%	low