Your DS or DD will know the exact dates but it starts up right after graduation and runs until the last weekend in June (or at least it did last year). There was no extra cost involved save driving 2 cars down so DS could have one for the summer session and then taking the train down to drive the car back.
As a bonus, the car was stuffed with all the stuff the B-splitters didn't want to trust to the lockers. I had enough uniforms to start my own private navy. Not to mention text books, printers, a set of weights and a chin up bar. Had to drive all that back down at the end of October when they came back.