Would this jacket keep me warm in like -15...
Would this jacket keep me warm in like -15 New York city winters?
No way. This has less than 2oz of 900 fill. If you have a windproof shell, that's enough to get you down to 20F. Maybe. Try a heavier jacket like the Mostbell frost or Outdoor research megaplume, Mountain Hardware sub-zero. If you run warm, perhaps the Marmot Ama Dablam would work. However, I suggest you get a jacket that works for 90% of the weather you encounter, not spend over 200 for those 5 days when it's that cold (not from NY so I don't know how cold it gets). The above jackets will make you sweat in anything above 20deg and if you do anything active. Get the Marmot AD, wear a shell over it, a light fleece and a wool long sleeve under if it gets that cold.... Or stay home. Hope that helps some.