Solar noon in Boston is somewhere between 11:27 and 11:58 EST (so an hour later EDT), but solar noon in San Francisco is somewhere between 11:53 and 12:23 PST.

Solar noon in Boston is somewhere between 11:27 and 11:58 EST (so an hour later EDT), but solar noon in San Francisco is somewhere between 11:53 and 12:23 PST. The earliest twilight in Boston is 4:11 PM; the earliest twilight in San Francisco is 4:50 PM (both in early December). That is, solar noon in San Francisco is pretty well lined up with civil noon or a bit later, and so DST makes it noticeably late, and our circadian rhythms prefer ending DST there. But solar noon in Boston is usually about half an hour earlier than civil time, which means that DST puts it just half an hour later instead. You have to pick one - either you're waking up half an hour earlier than your body wants, or you're staying at work half an hour later. Neither is really great. (The best solution might be to convince businesses in Boston to shift their schedules half an hour earlier - not a full hour earlier, as permanent DST does.)