You may be correct on this depending on the timeline. I think a lot of people are probably ignorant of how warm New England was in the late ‘40s through mid-50s. In fact, there’s a lot of sites in New England that still have their warmest year ever as 1949. At least when I checked a few short years ago. Maybe that list is smaller now, I’d have to check again.
But it shows just how extreme some of the warmth was around the middle 20th century here. So when we cooled in the following few decades, we had plenty of room to come back up as the underlying forcing asserted itself.
And yes, nighttime mins have warmed faster than daytime highs. That’s pretty consistent with the warming climate as higher vapor make rad cooling harder and it also makes the high-end temps more difficult to achieve (as we already discussed).
I do find the temporal/spacial differences fascinating in their own right.