Mercer Island, WA vs Sumner, WA

The cost of living difference between Mercer Island, WA and Sumner, WA is dramatic. Sumner is 97.7% cheaper than Mercer Island, a gap that translates to thousands of dollars per year in household expenses. Mercer Island has a cost index of 269 while Sumner sits at 136, making this one of the more striking comparisons on our site. Relocating between these cities would require a serious reassessment of budget and lifestyle expectations.

On the housing front, median rent in Mercer Island is $2,464/month compared to $1,886/month in Sumner — a 31% difference. Home values follow the same pattern: Sumner is more affordable at $478,500 median vs $1,884,200.

Median household income in Mercer Island is $202,359 compared to $98,376 in Sumner (+105.7%). While Mercer Island is more expensive, its higher salaries more than compensate — residents there may actually end up with more disposable income. Looking at affordability, residents of Mercer Island spend roughly 14.6% of their income on rent, less than the 23% in Sumner.

Climate-wise, both cities share similar average temperatures (53.8°F vs 53.7°F). Sumner receives more rainfall at 39.3" per year compared to 36.5" in Mercer Island.