Boston’s photographic calendar is set by academic terms rather than by weather. Commencement season runs from the first week of May through early June and involves a scale of graduation portraiture that no other American city matches at this density — Harvard, MIT, BU, Northeastern, BC and thirty more inside a half-hour radius. December adds a second, smaller wave. If you want campus photographs in those weeks, book months ahead; if you want a quiet campus, avoid them entirely.
The city itself is compact in a way that is genuinely useful. Beacon Hill, the Public Garden, the Esplanade and Back Bay are within a twenty-minute walk of each other, so a two-location session here does not lose half its time to transit — which makes Boston one of the best-value markets in this catalogue for anything with a fixed session length.
Campus access is the thing to check rather than assume. Most of these universities are private property, several require permission for professional photography on their grounds, and a few restrict it to affiliates. It is worth confirming before the morning of a graduation shoot.