The best anyone can do, without actually getting lucky and predicting it without any information, is this: http://guides.macrumors.com/MacBook_Pro_Buyer's_Guide
Other than that, almost everybody agrees that it is time for an upgrade and that it will come soon, given the above mentioned guide, this month seems likely. That's what most people know and if anybody actually knows 100% when this will happen, they haven't posted it here.
Other than that, almost everybody agrees that it is time for an upgrade and that it will come soon, given the above mentioned guide, this month seems likely. That's what most people know and if anybody actually knows 100% when this will happen, they haven't posted it here.