Pants? Shorts?

This may be a dumb question. We live in New England, so the weather is unpredictable in May/June. I’ll buy a couple sets of newborn & 0-3 pants just in case for colder days but...do babies wear shorts when it’s hot? Or just onesies? LOL. This seems dumb but I really don’t know! We’re having a boy, FYI. I feel like girls summer clothes are easier.