A couple of months ago I tried issuing a daily ~20h prediction based on a hunch that I though might work (the "Chinese Slumber Method"). But in the end it was not significantly better than the trivial method "tomorrow the price will be the same as today".
So my prediction for tomorrow at this hour on Bitstamp is 621.18 USD. Also for next year on this day, too.
I will lay 10:1 against your prediction for Jul 16, 2015. Will bet up to 1 Bitcoin.