Hello to those reside in/familiar with Seattle/Vancouver areas!

Our family will be visiting Seattle & Vancouver for a short stay (couple days/nights each). I have some general questions and any tips/advices are welcome!

- what is typical weather towards end of August (8/20 +)?
- how much rain?
- what are some kids places/ parks? Anywhere with mazes, hide-n-seek, just for running around?
- any indoor places for kids if lots of rain?
- any special restaurants (nothing fancy, kids friendly too)
- any specific places worth visiting (Boeing plant, space needle, Victoria...)?

This would my DH & I's 2nd trip to seattle/vancouver area, but last time we were newly married with no children. So this time around, Microsoft campus won't make the cut. Any suggestions welcome! Appreciate all your insights...