I've been riding since '69 and it seems that at least once per year I get caught in a "gulley washer" thunderstorm but in all of that time I've only been caught it two hail storms, once in CO and once in MT.

The one in MT in 2010? was the worst as we (me, my wife and another couple) were on three bikes, out-in-the-middle-of-nowhere, with no bridges, overpasses or buildings when it began!
I instantly realized when it was about to start do I "ducked" in behind the fairing and windshield and proceeded to "ride through it"!
(Hail storms are usually confined to a small area and IMHO it's better to keep riding vs stopping in it and waiting it out).

Thankfully we ALL were wearing rain gear and helmets!
My wife (who had been through the storm with me in CO years before) did and ducked behind the windshield on her Heritage for protection but my friend (riding and Ultra) sat upright and his face/cheeks got pummeled and his wife pushed her head into his back for protection but helmet actually had scratches on it!

It's important to remember that IF your bike has a detachable windshield it can also be quickly removed and used as a "hail shield" when you're crouched beside the kickstand side of your bike and ANY protection is far better than none!

 

Midwest and the hills of the Dakotas's in particular can get real nasty in the summers weather wise, I don't miss living in KC one little bit over that. The big month plus adventure my brother and I did around free Europe on harleys in1988, think we had maybe 10 days total, it wasn't raining. Try being completely clueless, coming off the ferry from France into England on Friday night, driving rain on the wrong side of the road and roundabouts in heavy traffic. Dropping down out of Amsterdam on the coastal rd during a big north seas gale making landfall was something I don't care to repeat, blowing so hard there were times we were hard on the chicken strips on the tires going in a straight line. Rain was coming in horizontally. About week into the trip I started running commando, gotten tired of fighting my ******* over my skivvies.

 

Doesn't matter what the weather outlook is in the hills, storms just pop up in any direction.

 

Man, that could not be any more true. But as we say in SD,,,,"Don't like the weather? wait 10 minutes and it will be different!"
Another one - Our state bird = "The Orange construction cone"