St. elmo is located in Fayette county Illinois with a geographic area of 1.5 square miles. The total population in St. elmo is 1,466 with 47.6% male and 52.4% female. Children under age 5 represent 7.2% of the population, under age 18 equal 24.1% of the population and over age 65 is 17.3% of the population. The median household income is $43,913, per capita income is $19,890. There are a total of 534 housing units with 86.7% owner occupied. Education includes 32.0% of residents that are high school graduates and 14.4% with a bachelor's degree or higher. The average temperature in St. elmo in the summer is 74 degrees, and in the winter 27 degrees.