Also note that the first Pascal and Polaris cards will be entry level cards. Higher end gaming cards with high bandwidth memory will be end of 2016/early 2017. NVidia will be called Polaris with HBM (if they even end up using it), and AMD is Vega.
Most people are awaiting these for gaming and 4k. So I think it's a safer bet to say it'll be 2017 before they are to market and readily available. It could be late 2016 though if they try to push them in time for the Christmas/School season.