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September Weather in Sun Prairie, United States

Last updated: June 24, 2025

In Sun Prairie, United States, the average temperature in September is a pleasant 18°C (65°F). However, you may experience fluctuations, with temperatures dipping as low as 2°C (36°F) and peaking at 33°C (92°F). Expect around 110 mm (4.3 in) of precipitation over 9 days, and a comfortable average humidity of 79%.

September Temperature in Sun Prairie

In September, in Sun Prairie, the average temperature is 18°C (65°F). The maximum can reach 33°C (92°F), while the minimum can be as low as 2°C (36°F). This temperature range makes Sun Prairie an ideal destination for travelers seeking both warm days and cool nights.

September Weather in Sun Prairie: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Sun Prairie, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Sun Prairie, September typically has an average temperature of 18°C (65°F), with highs reaching up to 33°C (92°F) and lows dropping to around 2°C (36°F).
JanFebMarAprMayJunJulAugSepOctNovDec212235455970747164513629
Data source: Temperature data for Sun Prairie 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 Sun Prairie

In Sun Prairie in September, the precipitation amount is 110 mm (4.3 in) over the course of 9 days.

September Precipitation Trends in Sun Prairie

The chart displays monthly precipitation patterns in Sun Prairie, 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 Sun Prairie, September typically receives around 110 mm (4.3 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec51535799130114991061101184346
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Sun Prairie

In Sun Prairie in September, humidity is 79%. With an average temperature of 18°C (65°F), this humidity feels like walking through a warm mist, making traveling slightly uncomfortable and sticky, but offering a refreshing escape when you find moments of shade or a breeze.

September Average Humidity in Sun Prairie

This chart illustrates the average monthly humidity levels in Sun Prairie, 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 Sun Prairie is approximately 79%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%85%85%85%78%80%78%76%79%83%88%82%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Sun Prairie

In Sun Prairie 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 Sun Prairie.

Maximum UV Index Levels in Sun Prairie for September

The chart shows the monthly maximum UV Index (UVI) for Sun Prairie 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 Sun Prairie typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec34589101098532
Data source: Sun Prairie 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 Sun Prairie Compares to Other Months

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

This table compares monthly weather conditions in Sun Prairie, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-6°C (21°F)51 mm (2.0 inches)85%moderate
February Weather-6°C (22°F)53 mm (2.1 inches)85%moderate
March Weather2°C (35°F)57 mm (2.3 inches)85%moderate
April Weather7°C (46°F)99 mm (3.9 inches)85%very high
May Weather15°C (59°F)130 mm (5.1 inches)78%very high
June Weather21°C (70°F)114 mm (4.5 inches)80%very high
July Weather24°C (75°F)99 mm (3.9 inches)78%very high
August Weather22°C (71°F)106 mm (4.2 inches)76%very high
September Weather18°C (65°F)110 mm (4.3 inches)79%very high
October Weather11°C (51°F)118 mm (4.6 inches)83%moderate
November Weather2°C (36°F)43 mm (1.7 inches)88%moderate
December Weather-2°C (29°F)46 mm (1.8 inches)81%low

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