I don't really know the answer, but I think that it's a similar situation to thunderstorms - wherever possible, the plane will simply change course.
It's bound to be a lot easier to avoid a hurricane by plane - the problems arise when the hurricane is due near to the landing airport and could not be avoided. I should imagine the only delays that would arise would be caused by too many planes having to share a smaller airspace.
Bet Obi Wan Kenobi knows the real answer though.