I live in central NJ, about 10 miles west of the coastline. That said, I am subject to occasional Nor’easters with high humid conditions and an occasional 12 plus inches of snow. My cold season temperatures usually range in the 20 to 40F range, occasionally dipping into the teens, but very rarely below 0. "Cold snaps", sustained temperatures below freezing, could easily last a few days, occasionally a week or more. Coldest coop temperature recorded in the last dozen or so years was -6F where daytime temperatures reached the low teens. Perhaps 2 or 3 times in the last dozen years have I witnessed this occurrence (below 0F ambient temperatures). My birds, water, and eggs, were still fine, nothing frozen. That was about 2 seasons ago, I have since stopped worrying about the cold. Everything is on autopilot.