Olympic National Park in May?

Hi! I'm planning on visiting Seattle/Olympic National Park in mid-May. Does anyone know what the weather is usually like around that time? Hoping we can skip the rain and see most of the sites, but not too sure what the best time is to visit.

Also, I currently have Hoh Rainforest, Mt. Storm King, Cape Flattery, Sol Duc Falls, and Ruby Beach on out itinerary. Any other places to add on?