I was there! haha.
My buddy lives in Lake Clear, NY and let my buddy down here (nutso hammock camper :o) and I know in advance, so we drove up there just for one night of hell.
I took my poncho tarp and my -25F Puma bag:
I think on average, this is what my friends and I plan for based off looking at historical data:
Down to zero degrees low in Catskills, usually around freezing give or take for a high temp during the day.
ADKs (Near Saranac Lake):
Average high during day 20F-32F, no higher. Plan for down to -15F in dead of night. Have seen the -30F+ on that one specific night, a -17F night (still decently rare), -9F and -6F as I recall on previous President's day long wknd trips.
As I transition to backpacking in the winter ( I tend to stay off big mtns in winter and snowshoe), not just car camping, I am going to shoot for a ~0F bag, then add hot water bottle, down booties, VBL, extra clothing etc. to go lower if called for.