Some orchards will have apples stored away that they will press at later months. The apple blend will change however. I think I've seen cider up to march last year. I was going with a gallon every few weeks.
The orchards themselves will close to the public, however they may still sell the cider elsewhere. For example, wasem fruit farm in Michigan only has their orchard open to visitors in the fall/winter. (not counting the summer berry picking though.) However, they sell their cider at the local farmer's market past December.
I have to pick up about 5 gallons soon.
But beyond that, like any agricultural product, there is a limit to how much you will see. Any cider found in the summer, for example, would be derived from apples either out of season, or from an outside source that has just had their season. Which is why where I am, I have michigan apples in the fall/winter and New Zealand apples in the Summer.