I am heading to ME in September with a group of friends checking out the state and then climbing Katahdin. I am considering turning in my round trip ticket and hiking sobo from there as far as I can or want to go starting on 9/24 at "The Birches". Weatherwise, I would think it will be a beautiful time to be doing this but I am wondering when it will start getting Really Cold up there? I Love hiking in the 60 & 70's for daytime temps but as I grow older I don't like the 20's and below at night. Plus not sure of where I would hit the exposed ridgelines that can be a challenge in ME, NH & VT in October/November? What temps can I expect on this type hike? Any other helpful info is appreciated! (disclaimer, I have LASH'd from Springer to NJ & thru-hiked the PCT sobo in 2016)

Thanks everyone!