What zone is New York City? I have heard that it is 7B. Is that correct?
Yes, according to the latest USDA Plant Hardiness Zone map New York City is in Zone 7b (i. e. lowest avergage winter temperature of 5-10°F). It is important to note, however, that this value is based on the average temperature over the 1976-2005 period. It is very likely that with global warming more recent averages could be higher. Another important point to remember is that these values are averages and occasionally temperatures in New York City can fall as low as 0-5°F.
Courtesy of NYBG Plant Information