September Weather in Three Rivers, United States

Last updated: June 24, 2025

In September, the average temperature in Three Rivers, United States is a comfortable 18°C (65°F). Expect lows of 3°C (38°F) on cooler days and highs reaching up to 31°C (89°F) during warmer spells. With an average precipitation of 91 mm (3.6 in) over 8 days, staying dry may require a light umbrella. Don't forget, the average humidity hovers around 71%, adding a touch of humidity to your daily adventures!

September Temperature in Three Rivers

In September in Three Rivers, the average temperature is 18°C (65°F), with maximums reaching 31°C (89°F) and minimums dipping as low as 3°C (38°F). This makes Three Rivers an ideal destination for travelers seeking a pleasant climate while exploring the local attractions.

September Weather in Three Rivers: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Three Rivers, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Three Rivers, September typically has an average temperature of 18°C (65°F), with highs reaching up to 31°C (89°F) and lows dropping to around 3°C (38°F).

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

September Precipitation in Three Rivers

In Three Rivers in September, the total precipitation amount is 91 mm (3.6 in) over the course of 8 days.

September Precipitation Trends in Three Rivers

The chart displays monthly precipitation patterns in Three Rivers, 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 Three Rivers, September typically receives around 91 mm (3.6 inches) of precipitation spread over approximately 8 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 Three Rivers

In Three Rivers in September humidity is 71%. With an average temperature of 18°C (65°F), this humidity feels like a warm embrace, making it a bit sticky and muggy, which can be slightly uncomfortable for traveling, especially if you're engaging in outdoor activities or exploring the city on foot.

September Average Humidity in Three Rivers

This chart illustrates the average monthly humidity levels in Three Rivers, 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 Three Rivers is approximately 71%, 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 Three Rivers

In Three Rivers 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 Three Rivers.

Maximum UV Index Levels in Three Rivers for September

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

Data source: Three Rivers 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 Three Rivers Compares to Other Months

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

This table compares monthly weather conditions in Three Rivers, 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 (28°F)	72 mm (2.8 inches)	86%	moderate
February Weather	-1°C (31°F)	90 mm (3.6 inches)	84%	moderate
March Weather	2°C (36°F)	82 mm (3.2 inches)	82%	high
April Weather	8°C (47°F)	126 mm (4.9 inches)	80%	very high
May Weather	14°C (58°F)	97 mm (3.8 inches)	72%	very high
June Weather	20°C (68°F)	84 mm (3.3 inches)	72%	very high
July Weather	23°C (74°F)	144 mm (5.7 inches)	67%	very high
August Weather	22°C (72°F)	84 mm (3.3 inches)	66%	very high
September Weather	18°C (65°F)	91 mm (3.6 inches)	71%	very high
October Weather	13°C (55°F)	139 mm (5.5 inches)	78%	high
November Weather	5°C (41°F)	95 mm (3.7 inches)	84%	moderate
December Weather	0°C (32°F)	125 mm (4.9 inches)	81%	low