Parent whose main interaction with their child or children occurs during one season of the year, usually their child's summer vacation from school. Seasonal dads have been known to take great offense when their motives or parenting skills are called into question.
We asked our friend to get a dna test on his kid who bears no resemblence. He got pissed off and lectured us and told us we don't know what its like to have a family. It's probably because he's a seasonal dad and doesn't see his kid too often.