The winter-heavy filming points towards the increased influence of the White Walkers, whom Jon Snow/Tarkgaryen will now presumably be turning his attention to now that he’s reclaimed the North.
Game of Thrones season 7 had a projected release date of April 2017, based on previous seasons, but it looks like we’ll be getting it a little late because of the weather.
“We’re starting a bit later because at the end of this season, ‘Winter is here’ – and that means that sunny weather doesn’t really serve our purposes any more.
So we kind of pushed everything down the line, so we could get some grim grey weather even in the sunnier places that we shoot.”