It can be for some adults who want to bowl with a lighter bowling ball but 13 pounds is not a bad weight. It is lighter than a 14 pound ball but depending on the person, 13 pounds is not bad at all. Is it too light? I would say 13 pounds is the lowest I would go as far as weight goes. Try a 14 pound bowling ball and if that is too heavy, then I would use a 13 pound bowling ball but it all depends on the bowler and how much can they handle.