Mount Vernon Weather in August

What's the weather like in Mount Vernon (Illinois) in August 2025?

The climate in Mount Vernon during August can be summarized as hot, humid and a little damp.

August is in the summer in Mount Vernon and is typically the 2nd warmest month of the year. Daytime maximum temperatures average around a muggy 31°C (87°F), whilst at night 18°C (64°F) is normal.

Mount Vernon weather averages (imperial / metric)
Daytime temperature 30.5°C 86.8°F
Nightly temperature 17.6°C 63.6°F
Average temperature 24°C 75.2°F
Daily sunshine 10.2 hrs
Avg rainfall 81 mm 3.2 ins
Rainy days 8 days
Sea temperature 23.2°C 73.7°F
Humidity 72%
Windspeed 11.9kph 7 mph

On average August is the 4th driest month of the year in Mount Vernon with around 81mm 3.2 inches of rain making it a a little damp time to visit. This rainfall is typically spread over 8 days, although this may vary considerably.

On the flip side this corresponds to an average of 10.2 hours of sunshine per day.

August temperatures in Mount Vernon

Mount Vernon average temperature in August

August rainfall

Mount Vernon average rain in August

August hourly sunshine

Mount Vernon average rain in August

The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Mount Vernon in August 2025.

Other monthly averages

Best places to visit in August

UV index Best time to go?

Beta

Current (hourly) weather 15 day forecast

Mount Vernon weather stats

Mount Vernon weather statistics
Hottest month: July 31.2°C 88.2°F
Driest month: January 59mm 2.3ins
Sunniest month: July 11hrs
Coldest month: January 3.1°C 37.6°F
Wettest month: May 113mm 4.4ins
Map showing location of Mount Vernon (38.31727, -88.90312) Mount Vernon map pin © Google

Locations nearby

Top United States locations