Also FWIW, the entire New England area may be prone to forest fires as bad as the west coast if the region continues to dry out. There is no management of brush in Maine or Vermont or New Hampshire (or even Canada for that matter).
You also can't exactly predict the effects of climate change on regions. I don't think anyone ever thought Washington or Oregon state would experience 24+ hour 100 degree heats during the summer, but they did and will likely experience it again in the future.
Unlikely, given that places nearer to the poles have experienced greater variations. But I don't think Boston is at existential risk or anything like that, with ample water sources and enough elevation aside from a few places.
It will be a fantastic place for HVAC contractors over the next few decades. Not enough homes have AC (and the ones that do are underpowered), and there's a huge imbalance of tradespeople vs. PMC-type people, so the former will be able to command much higher rates.
NYC this summer was disgustingly hot though! So maybe this Boston thing is a random statistical anomaly.