"Early autumn heat is not unusual, but we haven’t seen any extreme heat — meaning temperatures in the upper 80s or even 90s — in late September and October for quite a while.
We know that over the past several decades temperatures have warmed up, but what is interesting is that the absolute extreme highest temperatures in fall have not really changed. You might be surprised that our warmest temperatures after Sept. 20 mostly occurred prior to the year 2000. Of the top 20 warmest days in late September and early October, only one has occurred this century."
https://www.bostonglobe.com/metro/2019/09/17/first-new-england-will-see-frosty-weather-then-around-this-weekend-what-going/UOHsiadw2w0N9D2LRcGObI/story.html?p1=Article_Feed_ContentQuery