USAAAO — 2023 First Round

Here is a map of MIT and the surrounding area, where North points directly upwards, as taken from https://whereis.mit.edu: Leo is biking along the Harvard Bridge (marked as =A") when he stops and looks out at the river. Looking out downriver (to the right on this map) and parallel to the banks, he sees the Sun straight in front of him, peeking out from above the buildings, and has to avert his eyes to not be blinded. What part of the academic year is it?