I heard on a NYC trivia show that it is 27 seconds but I can't confirm it.
A New York minute is an informal term used to mean a very short period of time. The term refers to the common perception that the people in New York City are hurried and impatient. Johnny Carson once described a New York Minute as being the time it takes "From the (traffic) lights to turn green, till the guy behind you starts honking his horn"
The same as everywhere in the world.
A N.Y minute is the time it takes for you to snap your fingers.