Two New Yorkers looking to spend a few days in Scandinavia in January.
I understand the temperature and the lack of daylight, but I'm looking for input of the best city to visit for a few days. Stockholm or Copenhagen.
Go.

I like to match my travel time to the time I want for the places I visit. From that perspective, IMO, Stockholm easily deserves 5 full days (even in the long daylight hours of summer). IMO, Copenhagen can work more easily be seen in, say, 3 days, maybe 4 if you include Roskilde.... YMMV.

Since you are New Yorkers, the temperatures are hardly likely to bother you, nor the short days.

Both cities are perfect for short trips and are very popular weekend destinations.

Stockholm is more beautiful due to it's setting on many small islands, during winter the islands are covered in snow and is very pretty (if sunny): Copenhagen is a cool city with cool people and a great Nordic food scene but it is a smaller city than Stockholm. I would check out the attractions and see what appeals most - Stockholm has the Vasa Museum, Copenhagen has castles etc.

Ttt

Interesting idea....who has direct flights from NYC? (I'd be intereted myself)

SAS fly from EWR to CPH & ARN ,Norwegian fly JFK to CPH. Norwegian are a low cost airline but with new aircraft. For foodies, I would recommend CPH over Stockholm.

Odin thank you. I have visited Copenhagen twice for very brief stays but both were decades ago. Still, I guess I would lean toward Stockholm only cause I've never been. I think there's good food there as well, no? May I ask how would you classify Stockholm on the food front....fair? Good? (Promose not to hold you to it!) (Not necessarily looking for the NOMA-level places, maybe a step below those for the most part..)

I'd also prefer a city where we could walk to most of the interesting areas..are either of these more compact than the other?

Hope these intrusions will also help the OP make his or her choice...

You won't go hungry, there are definitely good places for food in Stockholm and you can walk to interesting areas, eg Gamla Stan (meaning old town & it's very picturesque). It is a very walkable city, especially in the summer. I would thoroughly recommend a visit.
In this restaurant, they cook everything on woodfire.

http://ekstedt.nu/en/

In both cities the weather will be similar to NYC but the days are MUCH shorter.

There is definitely more to see/do in Stockholm - I would want 5 days - plus day trips. Copenhagen you can do in 3 plus. But does neither one speak to you more when you look at the major sights?

Oh - and for breakfast, be prepared to see lots of herring (but you can eat around it).

As for herrings, they might be served as part of a breakfast buffet, but you are not obliged to select them, so no need to eat around it, just don't put on your plate to start with if you don't like them. I don't feel like herrings for breakfast but they are good for lunch. The herrings are marinated in various sauces, they are skinned and filleted with no bones so very easy to eat, some are fried and then marinated.

Why would anyone want to "eat around" herring? It sounds like a treat.