Huh, I'll have to ask my parents, who still live near Seattle. I left around the late 2000s, so I'm mostly talking about the 90s and early 2000s. It never hailed a lot (like 2-3 times/year), and thunderstorms happened a few times in the spring.
That said, more than 5 times in the spring would definitely be unusual. That, plus the bonkers 100F+ weather two years ago (I think? I wasn't there) is kinda nuts.