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September Weather in Trenton, United States

Last updated: June 24, 2025

In September, the average temperature in Trenton, United States is a pleasant 21°C (69°F). However, expect a range with minimums dipping to 2°C (37°F) and maximums soaring up to 37°C (98°F). The area experiences approximately 53 mm (2.1 in) of precipitation over about 6 days, contributing to an average humidity of 70%.

September Temperature in Trenton

In September in Trenton, the average temperature is 21°C (69°F). Maximum temperatures can reach 37°C (98°F), while minimums can drop as low as 2°C (37°F). It's advisable to pack for both warm days and chilly nights when traveling during this time.

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 (69°F), with highs reaching up to 37°C (98°F) and lows dropping to around 2°C (37°F).
JanFebMarAprMayJunJulAugSepOctNovDec302942506075787569514234
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 53 mm (2.1 in) over a span of 6 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 53 mm (2.1 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec1716664012255736553401521
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 70%. With an average temperature of 21°C (69°F), this humidity feels like a warm blanket that envelops you as you travel, making you feel sticky and a bit lethargic, yet it adds a certain tropical charm to your adventures.

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 70%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec73%80%64%64%76%79%77%79%70%64%75%78%
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.
JanFebMarAprMayJunJulAugSepOctNovDec3579101111109643
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-1°C (30°F)17 mm (0.7 inches)73%moderate
February Weather-2°C (29°F)16 mm (0.6 inches)80%moderate
March Weather6°C (42°F)66 mm (2.6 inches)64%high
April Weather10°C (50°F)40 mm (1.6 inches)64%very high
May Weather16°C (61°F)122 mm (4.8 inches)76%very high
June Weather24°C (75°F)55 mm (2.2 inches)79%extreme
July Weather26°C (78°F)73 mm (2.9 inches)77%extreme
August Weather24°C (75°F)65 mm (2.6 inches)79%very high
September Weather21°C (69°F)53 mm (2.1 inches)70%very high
October Weather11°C (52°F)40 mm (1.6 inches)64%high
November Weather6°C (42°F)15 mm (0.6 inches)75%moderate
December Weather1°C (34°F)21 mm (0.8 inches)78%moderate

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