nagantino,
I know what you mean. Basically, keep the inside liner dry and you'll be just fine. Just getting the outside soaked is key.
I live up on the Colorado Plateau, near the Grand Canyon. From about early July through September here we get thunderstorms off and on dumping easily 6 inches of rain in an hour. We even get snow!
I know what you mean about Ireland as well, I have family in Galway.
best advice I can give you: the nicer hats are more expensive, and feel soft, genteel, and fragile. But for the most part they ain't. They're worth every penny, and I'll never go below 50% beaver again! It ruined me!! But at the same time, I wear that hat most days of the week I'm outside. And that picture was taken after four years of snow, sleet, mud, grim, dust, dirt, hail, you name it pretty much. The dark brown definitely helps keep it looking clean. But at the same time it's been through hell and back and still looks almost as new as when I got it.
I used to think "distressing" hats wasn't great. I just figured, "the way I wear em, it'll happen." Yeah, it hasn't happened yet. People even ask me "why you wearing your dress hat?" especially at the fairs or rodeos. I just wink and say, "it ain't."
when it comes to cowboy hats, quality is way worth it.