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September Weather in Mendham, United States

Last updated: June 24, 2025

In September, the average temperature in Mendham, United States is a comfortable 20°C (69°F), with a minimum dipping to 6°C (42°F) and peaks reaching up to 35°C (95°F). Expect about 101 mm (4.0 in) of precipitation over 10 days, contributing to an average humidity level of 68%. Enjoy the balanced climate, perfect for both indoor and outdoor activities!

September Temperature in Mendham

In September in Mendham, the average temperature is 20°C (69°F). Maximums can reach 35°C (95°F), while minimums can drop as low as 6°C (42°F). This makes it an ideal time for travelers to experience a pleasant climate with warm days and cool evenings.

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

The chart illustrates September temperature patterns in Mendham, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Mendham, September typically has an average temperature of 20°C (69°F), with highs reaching up to 35°C (95°F) and lows dropping to around 6°C (42°F).
JanFebMarAprMayJunJulAugSepOctNovDec333641516171777568594437
Data source: Temperature data for Mendham 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 Mendham

In Mendham in September, the precipitation amount is 101 mm (4.0 in) spread over the course of 10 days.

September Precipitation Trends in Mendham

The chart displays monthly precipitation patterns in Mendham, 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 Mendham, September typically receives around 101 mm (4.0 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec7010410311613510614213610114286113
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Mendham

In Mendham in September, humidity is 68%. With an average temperature of 20°C (69°F), this humidity feels like a warm embrace, making outdoor exploration both refreshing and slightly sticky, requiring occasional breaks in the shade to stay comfortable while traveling.

September Average Humidity in Mendham

This chart illustrates the average monthly humidity levels in Mendham, 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 Mendham 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 Mendham

In Mendham 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 Mendham.

Maximum UV Index Levels in Mendham for September

The chart shows the monthly maximum UV Index (UVI) for Mendham 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 Mendham typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356810101098642
Data source: Mendham 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 Mendham Compares to Other Months

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

This table compares monthly weather conditions in Mendham, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (33°F)70 mm (2.7 inches)84%moderate
February Weather2°C (36°F)104 mm (4.1 inches)82%moderate
March Weather5°C (41°F)103 mm (4.1 inches)81%high
April Weather11°C (52°F)116 mm (4.6 inches)78%very high
May Weather16°C (62°F)135 mm (5.3 inches)69%very high
June Weather21°C (71°F)106 mm (4.2 inches)69%very high
July Weather25°C (77°F)142 mm (5.6 inches)62%very high
August Weather24°C (75°F)136 mm (5.4 inches)65%very high
September Weather20°C (69°F)101 mm (4.0 inches)68%very high
October Weather15°C (59°F)142 mm (5.6 inches)74%high
November Weather7°C (44°F)86 mm (3.4 inches)82%moderate
December Weather3°C (37°F)113 mm (4.4 inches)80%low

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