It will be winter below the equator. Fricking hot for us above the equator.
Winter is good for the cards, bad for your wallet (as difficulty will go up if there are more people south of the "boarder" so to speak).
At this point with ASICs I don't think the season matters anymore, with just 1 Avalon doing the work of 95 7970s, well not for BTC anyways...
Yes, should the network suddenly slow down to 50% no one would panic, and no media outlets would have a field day declaring bitcoin "hacked".