About Sumner, WASumner is located in Washington. Sumner, Washington has a population of 10,500. Sumner is less family-centric than the surrounding county with 29% households with children. The county percentage for households with children is 30%. The median household income in Sumner, Washington is $62,331. The median household income for the surrounding county is $69,338 compared to the national median of $61,963. The median age of people living in Sumner is 40.2 years. Sumner WeatherThe average high temperature in July is 76.91 degrees, with an average low temperature in January of 32.58 degrees. The annual precipitation is 41.22. Real estate near SumnerNearby Cities |