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September Weather in Mandan, United States

Last updated: June 24, 2025

In Mandan, United States, the average temperature in September hovers around 16°C (61°F), with a notable range between a minimum of -2°C (29°F) and a maximum of 35°C (96°F). During this month, expect about 56 mm (2.2 in) of precipitation spread over 6 days, and enjoy a comfortable average humidity of 69%.

September Temperature in Mandan

In September in Mandan, the average temperature is 16°C (61°F). Maximums can reach 35°C (96°F), and minimums can be as low as -2°C (29°F). Travelers should be prepared for a wide range of temperatures, making layers essential for comfort during their visit.

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

The chart illustrates September temperature patterns in Mandan, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Mandan, September typically has an average temperature of 16°C (61°F), with highs reaching up to 35°C (96°F) and lows dropping to around -2°C (29°F).
JanFebMarAprMayJunJulAugSepOctNovDec151330405569737061443122
Data source: Temperature data for Mandan 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 Mandan

In Mandan in September, the precipitation amount is 56 mm (2.2 in) spread over 6 days.

September Precipitation Trends in Mandan

The chart displays monthly precipitation patterns in Mandan, 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 Mandan, September typically receives around 56 mm (2.2 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec121626275264626056561622
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Mandan

In Mandan in September, humidity is 69%. With an average temperature of 16°C (61°F), this humidity feels like a mild, humid embrace, making travel enjoyable yet requiring a light layer for comfort while exploring.

September Average Humidity in Mandan

This chart illustrates the average monthly humidity levels in Mandan, 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 Mandan is approximately 69%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%88%78%75%76%79%78%78%69%71%82%84%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Mandan

In Mandan 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 Mandan.

Maximum UV Index Levels in Mandan for September

The chart shows the monthly maximum UV Index (UVI) for Mandan 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 Mandan typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2459810997532
Data source: Mandan 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 Mandan Compares to Other Months

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

This table compares monthly weather conditions in Mandan, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-9°C (16°F)12 mm (0.5 inches)84%low
February Weather-10°C (14°F)16 mm (0.6 inches)88%moderate
March Weather-1°C (30°F)26 mm (1.0 inches)78%moderate
April Weather4°C (40°F)27 mm (1.1 inches)75%very high
May Weather13°C (56°F)52 mm (2.0 inches)76%very high
June Weather20°C (69°F)63 mm (2.5 inches)79%very high
July Weather23°C (74°F)62 mm (2.4 inches)78%very high
August Weather21°C (70°F)60 mm (2.4 inches)78%very high
September Weather16°C (61°F)56 mm (2.2 inches)69%high
October Weather6°C (44°F)56 mm (2.2 inches)71%moderate
November Weather-1°C (31°F)16 mm (0.6 inches)82%moderate
December Weather-6°C (22°F)22 mm (0.9 inches)84%low

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