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June Weather in O'Fallon, United States

Last updated: June 24, 2025

In O'Fallon, United States, the average temperature in June hovers around 25°C (76°F), providing a pleasant climate for all. Temperatures can range from a cool 12°C (54°F) to a sweltering 37°C (99°F), so it's wise to prepare for anything! Expect about 84 mm (3.3 in) of precipitation over 11 days, resulting in an average humidity of 83%—perfect for those who enjoy a bit of tropical flair!

June Temperature in O'Fallon

In June in O'Fallon, the average temperature is 25°C (76°F). The maximum can reach 37°C (99°F) and the minimum can be as low as 12°C (54°F). This makes it an ideal time to visit for those who enjoy warm weather but should be prepared for both hot days and cooler evenings.

June Weather in O'Fallon: Daily Temperature Highs, Lows, and Averages

The chart illustrates June temperature patterns in O'Fallon, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In O'Fallon, June typically has an average temperature of 25°C (76°F), with highs reaching up to 37°C (99°F) and lows dropping to around 12°C (54°F).
JanFebMarAprMayJunJulAugSepOctNovDec323546556776797672594439
Data source: Temperature data for O'Fallon 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.

June Precipitation in O'Fallon

In O'Fallon, in June, the precipitation amount is 84 mm (3.3 in) during a period of 11 days.

June Precipitation Trends in O'Fallon

The chart displays monthly precipitation patterns in O'Fallon, with values for each month alongside June’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how June’s conditions compare to those of other months. In O'Fallon, June typically receives around 84 mm (3.3 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec72781281211458497139561106852
Data source: Precipitation data for June generated using information from the Copernicus Climate Change Service.
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June Humidity in O'Fallon

In O'Fallon in June humidity is 83%. With an average temperature of 25°C (76°F), this humidity feels like a heavy blanket enveloping you, making outdoor activities a bit more challenging and prompting frequent breaks for hydration.

June Average Humidity in O'Fallon

This chart illustrates the average monthly humidity levels in O'Fallon, with June’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In June, average humidity in O'Fallon is approximately 83%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%80%80%80%82%83%81%80%76%76%85%86%
Data source: Humidity data for June generated using information from the Copernicus Climate Change Service.

June UV Index in O'Fallon

In O'Fallon in June, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in O'Fallon.

Maximum UV Index Levels in O'Fallon for June

The chart shows the monthly maximum UV Index (UVI) for O'Fallon in June, 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 June, the maximum UV index in O'Fallon typically reaches 11, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3569101111109653
Data source: O'Fallon June 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 June Weather in O'Fallon Compares to Other Months

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

This table compares monthly weather conditions in O'Fallon, showing how June’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (32°F)72 mm (2.9 inches)82%moderate
February Weather2°C (35°F)78 mm (3.1 inches)80%moderate
March Weather8°C (47°F)128 mm (5.0 inches)80%high
April Weather13°C (55°F)121 mm (4.8 inches)80%very high
May Weather19°C (67°F)145 mm (5.7 inches)82%very high
June Weather25°C (76°F)84 mm (3.3 inches)83%extreme
July Weather26°C (80°F)97 mm (3.8 inches)81%extreme
August Weather24°C (76°F)139 mm (5.5 inches)80%very high
September Weather22°C (72°F)56 mm (2.2 inches)76%very high
October Weather15°C (59°F)110 mm (4.3 inches)76%high
November Weather7°C (44°F)68 mm (2.7 inches)85%moderate
December Weather4°C (39°F)52 mm (2.1 inches)86%moderate

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