I mostly think it'll go to $8 because of seasonal pattern and that Natgas prices have been down for a while now plus my own indicators.
I'm not sure what you mean by being able to get winter contracts for $6.75. Are you talking about the current month contract for futures? If that's the case, trading ends in a week so you can't hold til winter.
If you're looking into buying the spot, I have no idea how they take into account interests, storage, etc. so I really have no input on that.