September Weather in Cohasset, United States

Last updated: June 24, 2025

In September, the average temperature in Cohasset, United States is a pleasant 21°C (71°F). Expect a minimum temperature of 4°C (39°F) and a maximum of 40°C (105°F). During this month, precipitation totals around 15 mm (0.6 in) spread across 2 days, while the average humidity sits at a comfortable 44%.

September Temperature in Cohasset

In September in Cohasset, the average temperature is 21°C (71°F). Maximums can reach 40°C (105°F), and minimums can be as low as 4°C (39°F). Be prepared for a wide range of temperatures if you're planning to travel during this time!

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

The chart illustrates September temperature patterns in Cohasset, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Cohasset, September typically has an average temperature of 21°C (71°F), with highs reaching up to 40°C (105°F) and lows dropping to around 4°C (39°F).

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

September Precipitation in Cohasset

In Cohasset in September, the precipitation amount is 15 mm (0.6 in) over the course of 2 days.

September Precipitation Trends in Cohasset

The chart displays monthly precipitation patterns in Cohasset, 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 Cohasset, September typically receives around 15 mm (0.6 inches) of precipitation spread over approximately 2 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 Cohasset

In Cohasset in September humidity is 44%. With an average temperature of 21°C (71°F), this humidity feels like a comfortable and refreshing climate for traveling, allowing for enjoyable outdoor activities and leisurely explorations without feeling too sticky or oppressive.

September Average Humidity in Cohasset

This chart illustrates the average monthly humidity levels in Cohasset, 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 Cohasset is approximately 44%, 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 Cohasset

In Cohasset in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Cohasset.

Maximum UV Index Levels in Cohasset for September

The chart shows the monthly maximum UV Index (UVI) for Cohasset 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 Cohasset typically reaches 9, which falls under the very high exposure category.

Data source: Cohasset 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 Cohasset Compares to Other Months

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

This table compares monthly weather conditions in Cohasset, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	7°C (44°F)	200 mm (7.9 inches)	84%	moderate
February Weather	7°C (46°F)	206 mm (8.1 inches)	84%	moderate
March Weather	9°C (48°F)	177 mm (7.0 inches)	83%	high
April Weather	13°C (56°F)	90 mm (3.6 inches)	81%	very high
May Weather	17°C (63°F)	62 mm (2.4 inches)	74%	extreme
June Weather	23°C (73°F)	15 mm (0.6 inches)	64%	extreme
July Weather	27°C (81°F)	2 mm (0.1 inches)	44%	extreme
August Weather	26°C (78°F)	4 mm (0.2 inches)	36%	very high
September Weather	21°C (71°F)	15 mm (0.6 inches)	44%	very high
October Weather	15°C (60°F)	58 mm (2.3 inches)	65%	high
November Weather	10°C (50°F)	107 mm (4.2 inches)	84%	moderate
December Weather	6°C (43°F)	154 mm (6.1 inches)	83%	moderate