I'm going to Rio at the beginning of March. Every time I look at the weather there on Yahoo, it shows thunderstorms. Should I be worried, or does it typically rain for an hour or so, then stop?

I just got back last week from four days there. The weather is typical for tropical areas, with frequent cloudbursts that dump rain and then clear out. It was sunny practically the whole time we were there, but there are also usually towering clouds lingering in the area that can move it and make it pour for an hour or two.