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April Weather in St. Charles, United States

Last updated: June 24, 2025

In St. Charles, United States, the average temperature in April hovers around 9°C (48°F). Expect a wide range, with minimums plunging to -8°C (18°F) and maximums soaring to 29°C (84°F). Precipitation is notable, totaling 117 mm (4.6 in) over 13 days, while humidity remains high at an average of 85%.

April Temperature in St. Charles

In April in St. Charles, the average temperature is 9°C (48°F). The maximum can reach 29°C (84°F), and the minimum can be as low as -8°C (18°F). It's a diverse climate that can offer both warm days and chilly nights, so be sure to pack accordingly for your travels!

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

The chart illustrates April 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, April typically has an average temperature of 9°C (48°F), with highs reaching up to 29°C (84°F) and lows dropping to around -8°C (18°F).
JanFebMarAprMayJunJulAugSepOctNovDec242739486071757267543832
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.

April Precipitation in St. Charles

In St. Charles in April, the total precipitation amount is 117 mm (4.6 in) spread over 13 days.

April Precipitation Trends in St. Charles

The chart displays monthly precipitation patterns in St. Charles, with values for each month alongside April’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how April’s conditions compare to those of other months. In St. Charles, April typically receives around 117 mm (4.6 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec61598111716914010699911275453
Data source: Precipitation data for April generated using information from the Copernicus Climate Change Service.
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April Humidity in St. Charles

In St. Charles in April humidity is 85%. With an average temperature of 9°C (48°F), this humidity feels like a damp chill enveloping you, making outdoor activities less enjoyable and requiring extra layers to stay warm and comfortable while traveling.

April Average Humidity in St. Charles

This chart illustrates the average monthly humidity levels in St. Charles, with April’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In April, average humidity in St. Charles is approximately 85%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%83%84%85%79%82%80%81%80%82%88%84%
Data source: Humidity data for April generated using information from the Copernicus Climate Change Service.

April UV Index in St. Charles

In St. Charles in April, 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 St. Charles.

Maximum UV Index Levels in St. Charles for April

The chart shows the monthly maximum UV Index (UVI) for St. Charles in April, 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 April, the maximum UV index in St. Charles typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec34689101098632
Data source: St. Charles April 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 April 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 April’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 April’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-4°C (25°F)61 mm (2.4 inches)82%moderate
February Weather-3°C (27°F)59 mm (2.3 inches)83%moderate
March Weather4°C (39°F)81 mm (3.2 inches)84%high
April Weather9°C (48°F)117 mm (4.6 inches)85%very high
May Weather16°C (61°F)168 mm (6.6 inches)79%very high
June Weather22°C (72°F)140 mm (5.5 inches)82%very high
July Weather24°C (75°F)106 mm (4.2 inches)80%very high
August Weather22°C (73°F)99 mm (3.9 inches)81%very high
September Weather19°C (67°F)91 mm (3.6 inches)80%very high
October Weather12°C (54°F)127 mm (5.0 inches)82%high
November Weather3°C (38°F)54 mm (2.1 inches)88%moderate
December Weather0°C (32°F)53 mm (2.1 inches)84%low

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