The highest day temperature in August 2026 was 107°F. The lowest night temperature was 61°F. The average values for day and night temperatures during August were 93.3°F и 73.8°F respectivly.

Most of the days in August are sunny but you can also expect cloudy and gloomy days.

Precipitation total in August for Saint Charles is 1.4 in. It makes august one of the most rainy months of the year.

The average wind speed in August is 6.6 mph. It makes August one of the most windless months of the year for Saint Charles.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Saint Charles in August is 9.2 hours.