September Weather in Trenton, United States

Last updated: June 24, 2025

In September, the average temperature in Trenton, United States reaches a pleasant 27°C (80°F). However, temperatures can vary significantly, with a minimum of 17°C (63°F) and a maximum soaring to 37°C (99°F). Expect around 126 mm (5.0 in) of rainfall spread across 16 days, and keep in mind the average humidity is a high 83%.

September Temperature in Trenton

In September in Trenton, the average temperature is 27°C (80°F). Maximums can reach 37°C (99°F), and minimums can drop as low as 17°C (63°F). It’s a great time for travelers to enjoy the warm weather while exploring all that Trenton has to offer.

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

The chart illustrates September temperature patterns in Trenton, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Trenton, September typically has an average temperature of 27°C (80°F), with highs reaching up to 37°C (99°F) and lows dropping to around 17°C (63°F).

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

September Precipitation in Trenton

In Trenton in September, the precipitation amount is 126 mm (5.0 in), occurring over the course of 16 days.

September Precipitation Trends in Trenton

The chart displays monthly precipitation patterns in Trenton, 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 Trenton, September typically receives around 126 mm (5.0 inches) of precipitation spread over approximately 16 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 Trenton

In Trenton in September, humidity is 83%. With an average temperature of 27°C (80°F), this humidity feels like a warm, steamy embrace, making traveling a bit uncomfortable as the air clings to your skin and renders even the slightest exertion more exhausting.

September Average Humidity in Trenton

This chart illustrates the average monthly humidity levels in Trenton, 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 Trenton is approximately 83%, 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 Trenton

In Trenton in September, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in Trenton.

Maximum UV Index Levels in Trenton for September

The chart shows the monthly maximum UV Index (UVI) for Trenton 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 Trenton typically reaches 10, which falls under the very high exposure category.

Data source: Trenton 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 Trenton Compares to Other Months

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

This table compares monthly weather conditions in Trenton, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	14°C (57°F)	55 mm (2.2 inches)	83%	moderate
February Weather	17°C (63°F)	67 mm (2.6 inches)	82%	very high
March Weather	18°C (65°F)	35 mm (1.4 inches)	78%	very high
April Weather	21°C (70°F)	78 mm (3.1 inches)	77%	extreme
May Weather	25°C (77°F)	98 mm (3.9 inches)	75%	extreme
June Weather	27°C (80°F)	170 mm (6.7 inches)	76%	extreme
July Weather	27°C (81°F)	186 mm (7.3 inches)	79%	extreme
August Weather	27°C (82°F)	178 mm (7.0 inches)	78%	extreme
September Weather	27°C (80°F)	126 mm (5.0 inches)	83%	very high
October Weather	24°C (76°F)	72 mm (2.8 inches)	81%	very high
November Weather	18°C (64°F)	57 mm (2.2 inches)	83%	high
December Weather	15°C (60°F)	102 mm (4.0 inches)	86%	moderate