Mercer Island is located in Washington. Mercer Island, Washington has a population of 25,350. Mercer Island is more family-centric than the surrounding county with 33% households with children. The county percentage for households with children is 26%.
The median household income in Mercer Island, Washington is $147,015. The median household income for the surrounding county is $92,766 compared to the national median of $61,963. The median age of people living in Mercer Island is 48.3 years.
The average high temperature in July is 74.5 degrees, with an average low temperature in January of 36 degrees. The annual precipitation is 38.25.