I have just opened a position selling the spread NATURAL GAS FEB 2014 -
NATURAL GAS MAR 2014. The different in price has been +0.010 and I expect the different will go down to -0.030 before mid January 2014. Thus, around a benefit about 450$ per contract being conservative, without waiting to the limit.
Let's see..., here some graphs of this trading in different years, from Rankia.com :
Of course, this is not a recommendation of trading, just a log of some of my trading activity. Use this information at your own risk.