Why does it snow in new york city in winter

Because doesnt the ocean moderate new yorks climate a little bit, yes it is next to the atlantic ocean but considering also the internal heat from cars, trucks, buses, bikes etc generate heat

The ocean does moderate the local environment in the lower level of the atmosphere such that the rain / snow line if often right along or just inland from the coast...especially if the direction of low-wind comes from over the water.

NYC averages 29" of snow; whereas...Laguardia...JFK...and Islip...all closer to the coast...average slightly less (28"...24"...and 27").

When the low-level wind direction isn't a factor...the wind at higher levels from over the water increases the amount of moisture available for heavier snowfalls.

As for the effect from cars and track; the amount of heat given off by any kind of motor or engine pales in comparison to the cold air found aloft during a snow storm.

---
The 'thumbs down' crowd doesn't agree but note they don't offer a alternate explanation.

Snow doesn't form at the surface- it forms in the upper atmosphere. As long as the critical thickness in below 540, and the 850 millibar freeze line is south of New York, it can snow. If the surface temperature is below freezing, then the snow can stick. If your hypothesis were true, no major city would get snow fall.

its in the north, what else do you expect? im beginning to feel that you are from the south, maybe from georgia or alabama, and have never seen a single snowflake in your life. you need to toughen up and feel the beauty of a blanket of snow, rather than like four hundred thunderstorms you get every summer. btw, you lost the civil war!

the ocean and the heat island effect oes warm up the local climate a little bit, but not that much
some very cold air masses do affect the region, and those cold air masses often bring snow when they arrive