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September Weather in Mercer, United States

Last updated: June 24, 2025

In September, the average temperature in Mercer, United States is a comfortable 16°C (61°F). Expect a range from a brisk -1°C (31°F) to a warm 31°C (88°F). During this month, precipitation averages 69 mm (2.7 in) spread over 7 days, with an average humidity level of 77%.

September Temperature in Mercer

In September in Mercer, the average temperature is 16°C (61°F), with maximums reaching 31°C (88°F) and minimums dropping as low as -1°C (31°F). It's a great time for travelers to enjoy a mix of warm days and cool nights while exploring the beauty of Mercer.

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

The chart illustrates September temperature patterns in Mercer, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Mercer, September typically has an average temperature of 16°C (61°F), with highs reaching up to 31°C (88°F) and lows dropping to around -1°C (31°F).
JanFebMarAprMayJunJulAugSepOctNovDec192129415464696860493424
Data source: Temperature data for Mercer 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 Mercer

In Mercer in September, the precipitation amount is 69 mm (2.7 in) over the course of 7 days.

September Precipitation Trends in Mercer

The chart displays monthly precipitation patterns in Mercer, 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 Mercer, September typically receives around 69 mm (2.7 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec85847212787831218269129112116
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Mercer

In Mercer in September humidity is 77%. With an average temperature of 16°C (61°F), this humidity feels like a slight heaviness in the air, making every step feel a touch more effortful while traveling. The dampness clings to your skin, adding a layer of discomfort, yet the mild temperature invites you to explore the surroundings, blending the challenge of the humidity with an opportunity for a refreshing adventure.

September Average Humidity in Mercer

This chart illustrates the average monthly humidity levels in Mercer, 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 Mercer is approximately 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec91%89%85%84%78%72%75%74%77%85%86%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Mercer

In Mercer in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Mercer.

Maximum UV Index Levels in Mercer for September

The chart shows the monthly maximum UV Index (UVI) for Mercer 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 Mercer typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2458910987532
Data source: Mercer 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 Mercer Compares to Other Months

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

This table compares monthly weather conditions in Mercer, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-7°C (19°F)85 mm (3.3 inches)91%low
February Weather-6°C (22°F)84 mm (3.3 inches)89%moderate
March Weather-2°C (29°F)72 mm (2.8 inches)85%moderate
April Weather5°C (42°F)127 mm (5.0 inches)84%very high
May Weather12°C (54°F)87 mm (3.4 inches)78%very high
June Weather18°C (64°F)83 mm (3.3 inches)72%very high
July Weather20°C (69°F)120 mm (4.7 inches)75%very high
August Weather20°C (68°F)82 mm (3.2 inches)74%very high
September Weather16°C (61°F)69 mm (2.7 inches)77%high
October Weather9°C (49°F)129 mm (5.1 inches)85%moderate
November Weather1°C (35°F)112 mm (4.4 inches)86%moderate
December Weather-5°C (24°F)116 mm (4.6 inches)85%low

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