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September Weather in Willmar, United States

Last updated: June 24, 2025

In September, the average temperature in Willmar, United States is a pleasant 17°C (64°F), with temperatures ranging from a chilly 1°C (34°F) to a warm 33°C (91°F). Expect about 115 mm (4.5 in) of precipitation over 9 days, and stay prepared for high humidity levels averaging around 82%.

September Temperature in Willmar

In September in Willmar, the average temperature is 17°C (64°F), with maximums reaching up to 33°C (91°F) and minimums dropping as low as 1°C (34°F). This varying climate makes it essential to pack layers for your travels to Willmar.

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

The chart illustrates September temperature patterns in Willmar, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Willmar, September typically has an average temperature of 17°C (64°F), with highs reaching up to 33°C (91°F) and lows dropping to around 1°C (34°F).
JanFebMarAprMayJunJulAugSepOctNovDec151532425872747063473223
Data source: Temperature data for Willmar 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 Willmar

In Willmar in September, the precipitation amount is 115 mm (4.5 in) over the course of 9 days, indicating a relatively wet period for the region.

September Precipitation Trends in Willmar

The chart displays monthly precipitation patterns in Willmar, 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 Willmar, September typically receives around 115 mm (4.5 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec2022547610792105149115962639
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Willmar

In Willmar in September, humidity is 82%. With an average temperature of 17°C (64°F), this humidity feels like a damp embrace that can make traveling quite uncomfortable, as the sticky air clings to your skin and leaves you yearning for a cool breeze.

September Average Humidity in Willmar

This chart illustrates the average monthly humidity levels in Willmar, 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 Willmar is approximately 82%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%89%81%82%76%81%82%83%82%82%87%84%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Willmar

In Willmar 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 Willmar.

Maximum UV Index Levels in Willmar for September

The chart shows the monthly maximum UV Index (UVI) for Willmar 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 Willmar typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3567910997532
Data source: Willmar 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 Willmar Compares to Other Months

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

This table compares monthly weather conditions in Willmar, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-10°C (15°F)20 mm (0.8 inches)85%moderate
February Weather-10°C (15°F)22 mm (0.9 inches)89%moderate
March Weather0°C (32°F)54 mm (2.1 inches)81%high
April Weather6°C (42°F)76 mm (3.0 inches)82%high
May Weather15°C (59°F)107 mm (4.2 inches)76%very high
June Weather22°C (72°F)92 mm (3.6 inches)81%very high
July Weather23°C (74°F)105 mm (4.1 inches)82%very high
August Weather21°C (70°F)149 mm (5.9 inches)83%very high
September Weather17°C (64°F)115 mm (4.5 inches)82%high
October Weather8°C (47°F)96 mm (3.8 inches)82%moderate
November Weather0°C (33°F)26 mm (1.0 inches)87%moderate
December Weather-5°C (23°F)39 mm (1.5 inches)84%low

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