Grimes is located in Polk county Iowa with a geographic area of 11.8 square miles. The total population in Grimes is 13,746 with 49.6% male and 50.4% female. Children under age 5 represent 8.7% of the population, under age 18 equal 27.9% of the population and over age 65 is 6.9% of the population. The median household income is $89,113, per capita income is $38,257. There are a total of 5,331 housing units with 67.0% owner occupied. Education includes 23.8% of residents that are high school graduates and 48.5% with a bachelor's degree or higher. The average temperature in Grimes in the summer is 72 degrees, and in the winter 23 degrees.