The Honeycrisp season has lasted longer each year since I first discovered it shortly after moving to Iowa. It used to only be available from September through November; now I can buy them almost through January, when I have to return to the Pink Lady apples or Jazz apples to satisfy Max's picky palate.
I have to warn you, though, if you've never bought one before, be prepared for what seems to be a ridiculous price: usually around $2.99/pound. Also, since the seem to be more widely grown these days, you have to be careful about the quality. I suggest taking note of the brand name on the apple sticker and only buying one if you've never tried that brand before. If you find that brand to be delicious, you know if they're worth spending the extra money on. For those in the Des Moines area, the brand with the little brown bear logo is always good, and I find those at HyVee usually. The price can go down to $0.99/pound on sale, which is when I stock up on them, and they last a long time in the crisper drawer of my fridge.
If your store does not carry Honeycrisp apples, I suggest having a chat with the store manager, or taking your shopping list elsewhere, because these little gems are soooo worth it.