I did a trip with the
Dolphin Fleet out of Provincetown, in late May a couple of years ago. They always have a naturalist on board to answer questions and provide info, and they participate in data collection for researchers. On my trip we saw plenty of humpbacks, some minke, and one finback. I regret not having binoculars, as it was really difficult to see anything distinctive about the minke and finback. But on the other hand, it was awesome (in the traditional, awe-inspiring meaning) to see the humpbacks using bubble nets to catch their lunch.
The mixed blessing is that it's simply not worth going to Provincetown to just do a whale watch; you're better off picking up a boat in Boston. But if you're interested in other stuff around P'town and Cape Cod, then it's certainly worth picking up a whale watch here. An advantage is that P'town is closer to the usual feeding grounds, so there's less time spent just traveling to where the whales are.
right whales would be the prime targets.
Northern right whales are endangered, with only about 400 reported in the western North Atlantic (and nearly extinct in the eastern North Atlantic). If you see one, it will be a thrill of a lifetime, but don't count on it.
Humpbacks, on the other hand, have recovered well and are easy to find. We saw at least half a dozen on my one trip.
EDIT: Pick a location and call one of the tours to find out the best time to go. I think May worked well for me, because many of the whales are still on the migration north, and go through the feeding grounds off Cape Cod. But I didn't actually ask what the best time was.
