Mililani is located in Honolulu county Hawaii with a geographic area of 4.0 square miles. The total population in Mililani is 27,459 with 51.2% male and 48.8% female. Children under age 5 represent 5.3% of the population, under age 18 equal 20.2% of the population and over age 65 is 23.2% of the population. The median household income is $104,409, per capita income is $41,413. There are a total of 8,934 housing units with 79.7% owner occupied. Education includes 16.7% of residents that are high school graduates and 42.0% with a bachelor's degree or higher. The average temperature in Mililani in the summer is 85 degrees, and in the winter 78 degrees.