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September Weather in Merrill, United States

Last updated: June 24, 2025

In Merrill, United States during September, the average temperature hovers around 18°C (64°F). Expect a minimum as low as 0°C (33°F) and a maximum reaching 35°C (95°F). Keep an umbrella handy, as precipitation averages 96 mm (3.8 in) over 10 days, and be prepared for a humid environment with an average humidity of 80%.

September Temperature in Merrill

In September in Merrill, the average temperature is 18°C (64°F). Maximum temperatures can reach 35°C (95°F), while minimums can drop as low as 0°C (33°F). Dress in layers to enjoy the varied climate and take advantage of outdoor activities throughout the day.

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

The chart illustrates September temperature patterns in Merrill, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Merrill, September typically has an average temperature of 18°C (64°F), with highs reaching up to 35°C (95°F) and lows dropping to around 0°C (33°F).
JanFebMarAprMayJunJulAugSepOctNovDec242535455969747164523731
Data source: Temperature data for Merrill 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 Merrill

In Merrill in September, the total precipitation amount is 96 mm (3.8 in) over a span of 10 days.

September Precipitation Trends in Merrill

The chart displays monthly precipitation patterns in Merrill, 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 Merrill, September typically receives around 96 mm (3.8 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec565959861141147086961175962
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Merrill

In Merrill in September humidity is 80%. With an average temperature of 18°C (64°F), this humidity feels like a warm, damp blanket wrapping around you, making travel a bit more exhausting as the air thickens and the heat clings to your skin.

September Average Humidity in Merrill

This chart illustrates the average monthly humidity levels in Merrill, 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 Merrill is approximately 80%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%87%85%86%80%80%80%81%80%84%90%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Merrill

In Merrill 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 Merrill.

Maximum UV Index Levels in Merrill for September

The chart shows the monthly maximum UV Index (UVI) for Merrill 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 Merrill typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2458910997532
Data source: Merrill 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 Merrill Compares to Other Months

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

This table compares monthly weather conditions in Merrill, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-4°C (25°F)55 mm (2.2 inches)88%low
February Weather-4°C (26°F)59 mm (2.3 inches)87%moderate
March Weather2°C (35°F)59 mm (2.3 inches)85%moderate
April Weather7°C (46°F)86 mm (3.4 inches)86%very high
May Weather15°C (59°F)114 mm (4.5 inches)80%very high
June Weather20°C (69°F)114 mm (4.5 inches)80%very high
July Weather23°C (74°F)70 mm (2.7 inches)80%very high
August Weather22°C (71°F)86 mm (3.4 inches)80%very high
September Weather18°C (64°F)96 mm (3.8 inches)80%high
October Weather11°C (52°F)117 mm (4.6 inches)84%moderate
November Weather3°C (38°F)59 mm (2.3 inches)89%moderate
December Weather-1°C (31°F)61 mm (2.4 inches)86%low

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