Is there a way to check summer course midterm schedules so I can see when I can leave town

taking two summer courses

idk when the midterms are, ergo when I need to be in town for them

but I don't / can't wait until MAY when the courses start to ask the professors

because plane tickets are going to be so expensive if I buy them closer to July, for July

do I just buy them and hope it's fine??? i know I shouldn't leave town if i'm in class but it's not like i'm going on vacation .. Thanks