This is almost all I know of New England ski days from January through mid March. 15ºF is even a high temperature for many of those days, especially factoring in the wind chill
Now I'm having regrets for pulling the trigger on a shell.
don't regret it...layers > over insulation unless you don't care how many jackets you have. Layers offer better transfer of energy, mobility and heat. They stretch the dollar as well. Figure out layers instead of buying something you think will work for two months. The right shell can work almost all year. I have multiple jackets because I don't spend money on cocaine. But among my list, I have two shells that I can wear all year if I want.
If you figure out layers relative to body type you will never need an insulated jacket.
For example:
Shell - Goretex 2 or 3 with pit zips.
Patagonia Nano Air or Proton LT or Atom LT or similar breathable synthetic by OR or Mountain Hardwear
OR Puffy if super cold. (MH Ghostwhisperer is my favorite or Rab)
Then wool like 150-250+ Smartwool or Icebreakers underneath depending on thickness and mobility. OR Patagonia R-series
Every single piece can be sliced and diced all year long in any season. Your insulated jacket can not. But again, if you want multiple jackets, then do both.