Midwest Brides: April or August date?

Hi! My fiancé are having the TOUGHEST time picking a date. We are sort of limited to late April and mid August. We are getting married in Minnesota and weather is really taking a toll on our decisions. In April it could be cloudy and cold (also I work at a university in New England and he is in a grad program out of state so timing wise we are going to be a bit busier with work) and in August it could be super hot and humid (but we would have more time since school isn't going on). We are both VERY sweaty people and our tolerance for heat is virtually none, but the timing is much more convenient. Anyone have any thoughts on the matter that could help us make our decision?? Thanks so much!!