Two words: Long underwear.
It’s cold here in winter, and most visitors are utterly unprepared. Nobody considers New York an outdoor vacation spot like Hawaii, but it is. The coolest thing about New York is the bustle of its sidewalk life, the incredible variety of people and shops and buildings. If you come here without spending hours a day outside, walking the streets, you’ve wasted your trip. I’d suggest an excellent guided walking tour, of course, but guides or no guides, the streets are far and away the city’s best attraction.
Trouble is, most folks who come in winter come without anything resembling the amount of warm clothing they need to walk the streets comfortably. A heavy coat and a pair of gloves tossed over your normal clothing isn’t enough. Not even close. Cold is cumulative in a way that you cannot understand if your winter outings rarely last beyond the two minutes it takes you to get from your car to the door. The coat that seems so toasty during that two-minute walk will feel non-existent after 20 minutes outside.
So what do you need? Layers — particularly long underwear. One pair if you’re rarely cold in normal life. Two pairs if you’re always asking your husband to turn up the heat. You also want to make sure that the outer layer is always windproof because the gusts here will blow right through many fabrics. Nylon and leather work well on top. Dense materials work best on the bottom. Denim sucks.
Dress well and you’ll find that winter is a nice time to visit the city. Crowds plummet after New Year’s Day, so you can see sights easily and find bargains aplenty. But if you don’t bring enough warm stuff you’ll either miss the chance to really see the city or you’ll spend a lot of time in agony.
Here’s more general advice on the amount you need to pack for New York and tips on packing clothes that won’t make you look like a tourist.