Wentzville is located in St. charles county Missouri with a geographic area of 20.1 square miles. The total population in Wentzville is 40,407 with 49.7% male and 50.3% female. Children under age 5 represent 7.9% of the population, under age 18 equal 32.5% of the population and over age 65 is 11.0% of the population. The median household income is $93,602, per capita income is $35,631. There are a total of 13,458 housing units with 84.0% owner occupied. Education includes 17.9% of residents that are high school graduates and 41.7% with a bachelor's degree or higher. The average temperature in Wentzville in the summer is 76 degrees, and in the winter 32 degrees.