Blame sunny weather.
As if Game of Thrones fans weren’t already on the edge of their seats waiting for the next season premiere, the creators of the HBO series say they may have to wait a little longer.
Showrunners David Benioff and D.B. Weiss hinted at a delayed start to the seventh season this week while appearing on the UFC Unfiltered podcast (first reported by the New York Post). Amid a discussion of the writer-producers’ Ultimate Fighting Championship fandom, Benioff and Weiss were asked when fans can expect Game of Thrones‘s next-to-last season to debut on HBO. While previous seasons have premiered on the premium cable network during the month of April, Benioff and Weiss said the next season could actually be delayed.
The culprit? Good weather.
There is no firm premiere date yet, but the showrunners said it will “probably be a little later” because filming for the upcoming season will require more “grim,” cold weather, After all, the show’s longtime tagline has been “Winter is coming” and that long-promised colder weather had to show up onscreen at some point.
“We’re starting a little bit later, because at the end of this season, you know, ‘Winter is here,'” Benioff said on the podcast. “And, that means that sunny weather doesn’t really serve our purposes anymore, so we kind of pushed everything down the line so we could get some grim, grey weather, even in the sunnier places where we shoot.” Some of the series’ locales include Mediterranean settings such as Croatia, Morocco, and Spain.
Fortune reached out to HBO for a response to the comments from Benioff and Weiss. Network spokesman Jeff Cusson responded in an email that it is “too early to speculate” on when the seventh season of Game of Thrones will premiere.
Game of Thrones‘ explosive sixth season set ratings records for an already hugely popular cable series, and the show set a personal record with its season finale, for which 8.9 million people tuned in live or later the day it aired.
There had been some concern among Game of Thrones fans that the recent Brexit could affect filming in Northern Ireland, but HBO said last month that the U.K.’s decision to leave the European Union would not hurt the show. HBO has renewed the program for next season, and the network is also widely expected to sign on for an eighth, and final, season (which Benioff and Weiss have also recently teased).
Meanwhile, in the UFC podcast released on Wednesday, Benioff and Weiss also did not rule out the possibility of an eventual prequel series that would be set before the events of the current Game of Thrones.