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September Weather in Mundelein, United States

Last updated: June 24, 2025

In Mundelein, United States, the average temperature in September hovers around 19°C (67°F). However, you can expect a minimum of 5°C (42°F) and a maximum of 31°C (88°F) throughout the month. Expect 85 mm (3.3 in) of precipitation over approximately 10 days, contributing to an average humidity level of 79%.

September Temperature in Mundelein

In September in Mundelein, the average temperature is 19°C (67°F), with maximums reaching 31°C (88°F) and minimums dropping to as low as 5°C (42°F). This range makes it an ideal time for travelers to enjoy a variety of outdoor activities, from warm daytime explorations to cool evening experiences.

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

The chart illustrates September temperature patterns in Mundelein, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Mundelein, September typically has an average temperature of 19°C (67°F), with highs reaching up to 31°C (88°F) and lows dropping to around 5°C (42°F).
JanFebMarAprMayJunJulAugSepOctNovDec262737455668747267543933
Data source: Temperature data for Mundelein 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 Mundelein

In Mundelein in September, the precipitation amount is 85 mm (3.3 in) over the course of 10 days.

September Precipitation Trends in Mundelein

The chart displays monthly precipitation patterns in Mundelein, 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 Mundelein, September typically receives around 85 mm (3.3 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec6867761181641098483851335859
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Mundelein

In Mundelein in September, humidity is 79%. With an average temperature of 19°C (67°F), this humidity feels like a warm, enveloping blanket that makes traveling a bit more challenging, as the air is thick and can leave you feeling sluggish during outdoor adventures.

September Average Humidity in Mundelein

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

In Mundelein 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 Mundelein.

Maximum UV Index Levels in Mundelein for September

The chart shows the monthly maximum UV Index (UVI) for Mundelein 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 Mundelein typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec24689101098532
Data source: Mundelein 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 Mundelein Compares to Other Months

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

This table compares monthly weather conditions in Mundelein, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-3°C (26°F)68 mm (2.7 inches)85%low
February Weather-3°C (28°F)67 mm (2.6 inches)85%moderate
March Weather3°C (38°F)76 mm (3.0 inches)85%high
April Weather7°C (46°F)118 mm (4.6 inches)85%very high
May Weather14°C (57°F)164 mm (6.5 inches)78%very high
June Weather20°C (68°F)109 mm (4.3 inches)80%very high
July Weather23°C (74°F)84 mm (3.3 inches)78%very high
August Weather22°C (73°F)83 mm (3.3 inches)76%very high
September Weather19°C (67°F)85 mm (3.3 inches)79%very high
October Weather12°C (54°F)133 mm (5.2 inches)83%moderate
November Weather4°C (40°F)58 mm (2.3 inches)88%moderate
December Weather1°C (33°F)59 mm (2.3 inches)81%low

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