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September Weather in Trenton, United States

Last updated: June 24, 2025

In September, the average temperature in Trenton, United States hovers around 21°C (71°F). While the mercury can dip to a minimum of 6°C (43°F), it can also soar to a maximum of 33°C (93°F). Be prepared for some rainy days, as the region experiences about 96 mm (3.8 in) of precipitation over 8 days, complemented by an average humidity level of 72%.

September Temperature in Trenton

In September in Trenton, the average temperature is 21°C (71°F), with maximums reaching 33°C (93°F) and minimums dropping to as low as 6°C (43°F). This makes it an ideal time for travelers to enjoy a pleasant mix of warm and cooler days, allowing for versatile outdoor activities.

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 21°C (71°F), with highs reaching up to 33°C (93°F) and lows dropping to around 6°C (43°F).
JanFebMarAprMayJunJulAugSepOctNovDec283044526576797570554235
Data source: Temperature data for Trenton generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Trenton

In Trenton in September, the precipitation amount is 96 mm (3.8 in) over the course of 8 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 96 mm (3.8 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec564610485181142110103961375334
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Trenton

In Trenton in September, humidity is 72%. With an average temperature of 21°C (71°F), this humidity feels like a warm embrace, creating a thick, sultry atmosphere that can be quite heavy for traveling.

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 72%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec80%78%75%77%82%83%81%78%72%72%84%86%
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 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 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 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3569101111109643
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.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (28°F)56 mm (2.2 inches)80%moderate
February Weather-1°C (30°F)46 mm (1.8 inches)78%moderate
March Weather7°C (44°F)104 mm (4.1 inches)75%high
April Weather11°C (53°F)85 mm (3.4 inches)77%very high
May Weather18°C (65°F)181 mm (7.1 inches)82%very high
June Weather24°C (76°F)142 mm (5.6 inches)83%extreme
July Weather26°C (79°F)110 mm (4.3 inches)81%extreme
August Weather24°C (76°F)103 mm (4.1 inches)78%very high
September Weather21°C (71°F)96 mm (3.8 inches)72%very high
October Weather13°C (56°F)137 mm (5.4 inches)72%high
November Weather5°C (42°F)53 mm (2.1 inches)84%moderate
December Weather2°C (36°F)34 mm (1.3 inches)86%moderate

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