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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 (70°F). Expect a range where the minimum can dip to 6°C (43°F) while the mercury can soar up to 35°C (95°F). With 87 mm (3.4 in) of precipitation over approximately 10 days, and an average humidity of 68%, be prepared for a mix of conditions that can add both vibrancy and vitality to your visit.

September Temperature in Trenton

In September in Trenton, the average temperature is 21°C (70°F). Maximums can reach 35°C (95°F) and minimums can be as low as 6°C (43°F). This range makes it an ideal time for travelers seeking a variety of outdoor experiences, from warm afternoons to cooler evenings.

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 (70°F), with highs reaching up to 35°C (95°F) and lows dropping to around 6°C (43°F).
JanFebMarAprMayJunJulAugSepOctNovDec353843546372787670614639
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 87 mm (3.4 in) over the course of 10 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 87 mm (3.4 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec641091091061311001391358712183104
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 68%. With an average temperature of 21°C (70°F), this humidity feels like a warm embrace, making the air feel slightly heavy and sticky, which can be quite exhausting for travelers.

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 68%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%82%81%78%70%69%62%65%68%74%82%80%
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 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 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 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356810101098642
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 Weather2°C (35°F)64 mm (2.5 inches)84%moderate
February Weather3°C (38°F)109 mm (4.3 inches)82%moderate
March Weather6°C (43°F)109 mm (4.3 inches)81%high
April Weather12°C (54°F)106 mm (4.2 inches)78%very high
May Weather17°C (63°F)131 mm (5.1 inches)69%very high
June Weather22°C (73°F)100 mm (3.9 inches)69%very high
July Weather26°C (78°F)139 mm (5.5 inches)62%very high
August Weather24°C (76°F)135 mm (5.3 inches)65%very high
September Weather21°C (70°F)87 mm (3.4 inches)68%very high
October Weather16°C (61°F)121 mm (4.8 inches)74%high
November Weather8°C (46°F)83 mm (3.3 inches)82%moderate
December Weather4°C (39°F)104 mm (4.1 inches)80%low

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