Pair of board shorts and a T-shirt should be fine. Pick up a pair of waders (non-neoprene) if you really want to. Check out sports authority. Cotton has a tendency to stay wet and chill you in the cool air and wind. Synthetic fiber is the way to go(polyproplene). Little Marine Corps trick
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paddling gear is spendy and really isn't needed 9 months out of the year. I think a new pair of waders run around $80 - $120...