I have a chance to fly into Boston for the day on May 25th. Would this be a good time to go or would June 1st be better. Does anyone know when the graduations are?

It's Memorial Day weekend, alot of colleges are having graduations then. I see no reason why you can't come to the city for the day. It could be a bit more difficult to get a dinner reservation somewhere. I imagine people would go to dinner to celebrate graduation. Come and enjoy Boston for the day. May 25 or June 1 won't matter much at all.

June 1 would be beter for avoiding graduations, most of them are over by then except Harvard and MIT, which are June 6 and 7.

Would we be better off to wait until the 3rd weekend of June or will it be crowded with families of vacation then. Thanks

For both better weather and less crowding, June 1 would be better than later in the month. The public schools in Massachusetts start summer vacation around June 20, but the private schools get out earlier, and so do public schools in many parts of the country.