what fruits are in season?!
It depends on where you are trying to shop? Also are you wanting what is in season locally or what is available to purchase at a local grocery but maybe from elsewhere.
Where are you? For a lot of us, what's in season this time of year is citrus.
Per previous comments, where are you? Fruit is a global business. If you are in N. America your fruit might be coming from anywhere between Chile and Israel or Australia. If you want something fresh buy it close to where it's actually grown. Some crop cycles are off right now because of weird weather patterns. Get used to it.
I am in the UK right now and shop from both the local fruit and veg market and superstores.
And that last link looks very useful.
Locally - Tangerine, oranges and grapefruits are at their best.
I've been using cranberries, pumpkin, kubocha squash, kale, onions, potatoes, apples, pears, pomegranates, beets and some hydroponic herbs. If you live in the Northeast, you could also go by this chart: http://www.grownyc.org/greenmarket/whatsavailable
I've got greengages in season now. They're the best!