weather in sumner, wa
1 There is 26 percentage chance of rain and 4 mph winds from the North. 2  8pm:The Sumner, WA forecast for Aug 20 is 94 degrees and Sunny. There is 30 percentage chance of rain and 3 mph winds from the North-Northeast.  11pm:The Sumner, WA forecast for Aug 20 is 87 degrees and Clear.