The INSIDER Summary:

The eighth and final season of "Game of Thrones" won't air until 2019.

HBO confirmed the final season will only be six episodes long.

But each episode could be "feature film" length.

There are also weather reasons to take into account, since winter arrived to Westeros.

Plus the amount of post-production needed for the White Walkers and dragons will add to the longer time required.

As the penultimate season of "Game of Thrones" came to a close in 2017, fans were already looking ahead at the epic series' true conclusion. After several months of guesswork from fans and cryptic teases from actors and executives, HBO finally confirmed "Game of Thrones" won't be returning to TV this year. Instead it's airing sometime in 2019.

You might be wondering why the wait is so much longer this time around. Thankfully, there are several epic reasons for the extended production time.

Kit Harington as Jon Snow on "Game of Thrones" season seven. HBO

Winter arriving in Westeros means extended filming time

For its first six seasons, "Game of Thrones" consistently aired in the spring of each year. 2017 was the first year the show returned during the summer instead, with the seventh season premiering on July 16. This was mainly due to production being pushed back in order to accommodate the "winter" needs for outdoor filming.

Season eight is sure to feature a large number of chilly outdoor scenes, which means filming will once again be timed with the winter months. Filming for the new season started even later than usual, in October 2017.

Plus the total time spent filming is going to be longer (even though there are fewer episodes). Reports show that "Game of Thrones" will shoot season eight from October 2017 until around June 2018 — about nine months instead of the typical six.

Liam Cunningham, who plays Ser Davos Seaworth, spoke with TV Guide about what this means.

"We're filming right up until the summer," Cunningham said. "When you think about it, up until last season we'd have six months to do 10 episodes, so we're [doing] way more than that for six episodes. So that obviously will translate into longer episodes."

The added length to season eight's episodes

As Cunningham explained, the extended filming will likely contribute to longer total episodes. While the average "Game of Thrones" episode is just under one hour, it's possible several of the season eight installments will go well over that length.

"Game of Thrones" sound designer Paula Fairfield broke this news at the first annual Con of Thrones last summer. According to Fairfield, the final season might consist of six movie-length episodes.

The season seven finale, "The Dragon and the Wolf," was 79 minutes and 43 seconds (HBO specified the exact length in a press release). The idea of having six finale-worthy episodes is exciting, but there's no confirmation of this yet.

Entertainment Weekly's James Hibberd put a damper on the idea of all six episodes being more than an hour long, though.

"While some episodes may be longer than usual, once again we're hearing not to expect feature-length episodes throughout the season," Hibberd reported in January 2018.

The added need for visual effects and post-production

From here it's all guesswork, but we're betting "Game of Thrones" season eight will have more visual effects than any previous season of the show. With the Night King and his army of undead wights marching into Westeros, it only makes sense that the "Game of Thrones" team would need more time in post-production than usual.

And even though one of Daenerys' dragons was mercilessly killed off last season, there are still two giant beasts the VFX team needs to render. Given that the remaining dragons are heading to war, there's no skirting around the need for more digital effects.

Plus "Game of Thrones" fans will likely riot if Jon Snow's direwolf, Ghost, doesn't appear in at least one epic season eight scene. The wolf was offscreen for all of season seven, though we did get a glimpse of Arya's direwolf Nymeria.

According to reports from season seven, the reason for the lack of Ghost was partially due to the CGI costs associated with bringing him to life. But HBO surely can't avoid ponying up for at least one Ghost scene in the final season — right? Again, this means more time and effort from the post-production team.

Last but not least, there's small poetic reason why a spring 2019 air date would be ideal for final "Game of Thrones" season. The "A Song of Ice and Fire" novels upon which "Game of Thrones" was based is currently planned as a seven book series. Author George R.R. Martin titled the final book "A Dream of Spring," indicating the end (or at least dreamed end) of the coming winter.

If HBO times the conclusion of "Game of Thrones" in the spring season (which was always the traditional air date anyways), it would be a nice nod to fans of the original book series.

Of course, Martin's final two books have yet to be published. We're still waiting on the sixth book in the series, "The Winds of Winter." But that's a story for another time.

While we start the long wait for season eight, read our list of 21 key predictions we have for the final episodes of "Game of Thrones" in the meantime.