Johnstown is located in Weld county Colorado with a geographic area of 13.8 square miles. The total population in Johnstown is 14,357 with 53.7% male and 46.3% female. Children under age 5 represent 7.6% of the population, under age 18 equal 27.1% of the population and over age 65 is 11.1% of the population. The median household income is $115,069, per capita income is $38,869. There are a total of 4,858 housing units with 85.2% owner occupied. Education includes 18.3% of residents that are high school graduates and 34.8% with a bachelor's degree or higher. The average temperature in Johnstown in the summer is 68 degrees, and in the winter 29 degrees.