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September Weather in Oconomowoc, United States

Last updated: June 24, 2025

In Oconomowoc, United States, the average temperature in September hovers around 18°C (66°F). However, temperatures can range from a brisk 2°C (36°F) to a warm 34°C (93°F). During this time, precipitation averages 97 mm (3.8 in) over the course of 9 days, contributing to an average humidity level of 79%.

September Temperature in Oconomowoc

In September in Oconomowoc, the average temperature is 18°C (66°F). Maximum temperatures can reach 34°C (93°F), while minimums can drop as low as 2°C (36°F). Be prepared for a range of temperatures; pack accordingly for both warm days and cooler nights!

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

The chart illustrates September temperature patterns in Oconomowoc, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Oconomowoc, September typically has an average temperature of 18°C (66°F), with highs reaching up to 34°C (93°F) and lows dropping to around 2°C (36°F).
JanFebMarAprMayJunJulAugSepOctNovDec222336465970757265523730
Data source: Temperature data for Oconomowoc 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 Oconomowoc

In Oconomowoc in September, the total precipitation amount reaches 97 mm (3.8 in) over the course of 9 days.

September Precipitation Trends in Oconomowoc

The chart displays monthly precipitation patterns in Oconomowoc, 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 Oconomowoc, September typically receives around 97 mm (3.8 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec5651601081291119986971134646
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Oconomowoc

In Oconomowoc in September, humidity is 79%. With an average temperature of 18°C (66°F), this humidity feels like a warm, enveloping blanket, making outdoor activities slightly uncomfortable and sticky, but also offering a vibrant atmosphere perfect for exploring local cafes and shaded parks.

September Average Humidity in Oconomowoc

This chart illustrates the average monthly humidity levels in Oconomowoc, 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 Oconomowoc 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 Oconomowoc

In Oconomowoc 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 Oconomowoc.

Maximum UV Index Levels in Oconomowoc for September

The chart shows the monthly maximum UV Index (UVI) for Oconomowoc 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 Oconomowoc typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec34589101097532
Data source: Oconomowoc 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 Oconomowoc Compares to Other Months

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

This table compares monthly weather conditions in Oconomowoc, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-6°C (22°F)56 mm (2.2 inches)85%moderate
February Weather-5°C (24°F)51 mm (2.0 inches)85%moderate
March Weather2°C (36°F)60 mm (2.4 inches)85%moderate
April Weather8°C (46°F)108 mm (4.3 inches)85%very high
May Weather15°C (59°F)129 mm (5.1 inches)78%very high
June Weather21°C (70°F)111 mm (4.4 inches)80%very high
July Weather24°C (75°F)99 mm (3.9 inches)78%very high
August Weather22°C (72°F)86 mm (3.4 inches)76%very high
September Weather18°C (66°F)97 mm (3.8 inches)79%high
October Weather11°C (52°F)113 mm (4.5 inches)83%moderate
November Weather3°C (37°F)46 mm (1.8 inches)88%moderate
December Weather-1°C (30°F)46 mm (1.8 inches)81%low

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