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October Weather in St. Charles, United States

Last updated: June 24, 2025

In October, the average temperature in St. Charles, United States is a comfortable 17°C (64°F), with fluctuating conditions that can see lows of 4°C (39°F) and highs reaching up to 35°C (95°F). Expect 108 mm (4.2 in) of precipitation spread over about 9 days, contributing to an average humidity of 81%. Be prepared for a mix of pleasant warmth and occasional rain!

October Temperature in St. Charles

In October in St. Charles, the average temperature is 17°C (64°F). The maximum can reach 35°C (95°F) and the minimum can be as low as 4°C (39°F). This makes it an ideal destination for travelers seeking a pleasant climate with comfortable daytime temperatures and cooler evenings.

October Weather in St. Charles: Daily Temperature Highs, Lows, and Averages

The chart illustrates October temperature patterns in St. Charles, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In St. Charles, October typically has an average temperature of 17°C (64°F), with highs reaching up to 35°C (95°F) and lows dropping to around 4°C (39°F).
JanFebMarAprMayJunJulAugSepOctNovDec384248586776817873634943
Data source: Temperature data for St. Charles 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.

October Precipitation in St. Charles

In St. Charles in October, the precipitation amount is 108 mm (4.2 in) spread over 9 days.

October Precipitation Trends in St. Charles

The chart displays monthly precipitation patterns in St. Charles, with values for each month alongside October’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how October’s conditions compare to those of other months. In St. Charles, October typically receives around 108 mm (4.2 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec62937799118106122151911087886
Data source: Precipitation data for October generated using information from the Copernicus Climate Change Service.
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October Humidity in St. Charles

In St. Charles in October, humidity is 81%. With an average temperature of 17°C (64°F), this humidity feels like walking through a warm mist, enveloping you in a sticky embrace that can quickly lead to discomfort during long sightseeing excursions.

October Average Humidity in St. Charles

This chart illustrates the average monthly humidity levels in St. Charles, with October’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In October, average humidity in St. Charles is approximately 81%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%83%83%81%78%79%74%72%75%81%85%84%
Data source: Humidity data for October generated using information from the Copernicus Climate Change Service.

October UV Index in St. Charles

In St. Charles in October, 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 St. Charles.

Maximum UV Index Levels in St. Charles for October

The chart shows the monthly maximum UV Index (UVI) for St. Charles in October, 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 October, the maximum UV index in St. Charles typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec357910101098753
Data source: St. Charles October 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 October Weather in St. Charles Compares to Other Months

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

This table compares monthly weather conditions in St. Charles, showing how October’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather4°C (39°F)62 mm (2.4 inches)84%moderate
February Weather6°C (42°F)93 mm (3.7 inches)83%moderate
March Weather9°C (48°F)77 mm (3.0 inches)83%high
April Weather14°C (58°F)99 mm (3.9 inches)81%very high
May Weather19°C (67°F)118 mm (4.6 inches)78%very high
June Weather24°C (76°F)106 mm (4.2 inches)79%very high
July Weather27°C (81°F)122 mm (4.8 inches)74%very high
August Weather26°C (79°F)151 mm (5.9 inches)72%very high
September Weather23°C (73°F)91 mm (3.6 inches)75%very high
October Weather17°C (64°F)108 mm (4.2 inches)81%high
November Weather9°C (49°F)78 mm (3.1 inches)85%moderate
December Weather6°C (43°F)86 mm (3.4 inches)84%moderate

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