What is the difference between

Nymex Henry Hub

Henry Hub

and New York City Gate?

And why do they differ so much?

NYMEX HB = $12.32 and Henry Hub is $2 more. NYC Gate is $15.

Could someone explain those numbers?

Not sure on your Henry Hub price vs Henry Hub NYMEX, maybe spot vs future (today vs next month) but NYC gate is the citygate price for gas physically in NYC vs Henry Hub in Lousiana. Transport fees and fuel usage would make NY MMBTU more expensive than HH MMBTU.