Vandalia, in Illinois, United States, is home to roughly 7,100 people in the Central Time Zone at 39°N latitude.
Recent weather here gives a sense of typical conditions: in 2025, Vandalia recorded a mean annual temperature of 55°F, ranging from -2°F lows in January to 94°F highs in September, with about 35 inches of precipitation across the year.
View historical weather for Vandalia · More cities in Illinois