Season 6 of Supernatural aired between September 24, 2010 and May 20, 2011.

Timeline

August 30, 2009: Fans and the media had been speculating about a sixth season since before season 5 even started airing. In comments to Ausiello of EW in August 2009, Kripke confirmed he would wrap up the apocalypse storyline in season 5: "I’m looking at this season as the last chapter in this particular story. That doesn't mean there can’t be a new story."

January 10, 2010: Ausiello reported that Dawn Ostroff, president of the CW and Kripke had done lunch, and reported that Supernatural creator Eric Kripke is warming to the idea of a sixth season.

“I think he’s in that state of mind,” she says. “I had lunch with Eric the other day and he’s really excited about the show right now. I think he feels this season has been really satisfying for him. He’s certainly not running out of ideas by any stretch of the imagination.”
Ostroff, who says Kripke has been “hitting it out of the park” creatively [in season 5], also points to Supernatural’s ratings success as proof the show has a lot of life left in it. “The ratings are up,” she says. “We have more young women coming to the show than ever before. There aren’t a lot of shows that you can say are doing better in their fifth year.”

January 15: Kripke did speak about his vision for a sixth season, when asked how he would "top the Apocalypse"

Well, the trick is to not go big but go intimate – at least those are the initial conversations we've had [if the show is picked up for a sixth season]. We always set up this five-year storyline, because in my heart of hearts, I just never imagine we’d actually go five years, much less beyond. We are going to climax the storyline and really wrap up the story of Satan and Michael and the apocalypse. The big question is, how do you follow that? We look at this as a unique challenge but also an opportunity to really launch a new storyline next year. We’re almost looking at it as the sequel to a movie.

Rather than as a lot of genre shows do as they get on in years, becoming so convoluted and almost collapsing under their own mythology and getting to the point where you just can’t follow any of it anymore, we’re really looking forward to the opportunity of just sweeping it all clean and starting over with something else. We talk about returning to a stripped-down version of the show that’s almost similar to season one, in which the mythology was just as simple as finding their father and finding something that’s really personal and meaningful to Sam and Dean.

Season Six Promotional Poster

One of the things that’s hard about the end of the world is sometimes it’s hard to have your characters emotionally connect with it, because it’s so big. But if their emotional storyline for, say, season six is to save a loved one, then that’s something you can really understand and get behind and actually have some really emotional storytelling that takes you through a lot of the scary episodes.

January 21: Cinema Spy reported on 21 January 2010 that Season 6 was confirmed, but other sources were quick to deny it.

January 30: Season 6 talk from the 100th episode party:
- Sera Gamble talks about Season 6, and thanks the fans
- Misha talks season 6, and pranks by Jared

February 16: Following months of speculation and rumours, it was confirmed that Supernatural would return for a sixth season on the CW.

The official CW press release said:

The network also renewed fan favorite SUPERNATURAL, which will enter its sixth season next year. SUPERNATURAL has one of the most loyal audiences of any show on television and does heroic work in a perennially tough time period. It has improved over last season among women and adults 18-34 (29% and 8%, respectively) this season, a remarkable accomplishment for a fifth-year show.

Excitement at the news saw Supernatural reach #5 on trending topics on Twitter.

However, Michael Ausiello reported that Eric Kripke will step aside as show runner to devote more time to new projects with the WB. Sera Gamble is promoted to showrunner. Ausiello reports a source saying: “Eric and Bob will be working very closely with Sera. They are not abandoning the show."

Maureen Ryan of the Chicago Tribune got further confirmation of Kripke's ongoing involvement and asked Sera about whether season 6 would be "The Apocalypse 2: The Squeakquel".

"No, you will not be getting Apocalypse, The Squeakquel in Season 6 (that's hilarious)," Gamble wrote. "We're climaxing that story this season. We've been working on the Season 6 storyline for quite some time, and we're very excited about it. We have lots of ideas, and are grateful for the chance to keep the show going.
"Please tell the fans that the writers say thank you! We so appreciate the support."

Early speculation on what Season 6 may be like:
- Supernatural after Kripke by cinemablend
- Will Misha appear in season 6?

May 4: From TV Guide via Digital Spy.

Gamble also revealed that she is looking forward to working on the sixth season of the show.
"We'll go intimate and personal and, now that we've buttoned up the big destiny versus free will debate, explore a whole new set of questions," she said. "We're chomping at the bit."

May 8: Speculation in Variety that Supernatural may move to Friday night, and start mid-season (ie January 2011)

Sell sheet poster from the CW Upfronts May 2010.

May 10: Jensen talks season 6:

“Eric (Kripke, creator of Supernatural) wasn't going to tap the breaks when they found out they were going an extra year,” Ackles said. “He wasn't going to stretch five years over six. He was like, ‘I am going to do the five seasons, knock it out of the park and then figure it out from there.’

“So for me, my anticipation of the first script of Season 6 is going to be higher than almost any season.”

“I was just talking to Josh Jackson (currently of Fringe) who did six years on Dawson’s Creek,” Ackles said. “He goes, ‘You are moving into your sixth season (on Supernatural), aren't you?’ And I did the sixth season of Dawson’s Creek with him.

“I said, ‘I remember you guys (on Dawson’s Creek) were just champing at the bit to get out of there.’ He said, ‘Yeah — are you about ready to be done?’
“And I’m like, ‘No, I’m not, actually.’ ”

May 13: TV Guide talks to Sera Gamble on the finale and about season 6:

“Our main concern was not to slice the mythology thinner to drag it out any longer than it was designed to,” says Supernatural executive producer Sera Gamble. “That seems like a mean thing to do to viewers in exchange for making you successful and keeping you on the air. We want existing storylines to run their course, and then we figure it’s our job to bring in new stories.”

“I feel like I helped raise these two little brothers,” Gamble says with pride. “They’ve deepened so much over the years and they continue to evolve.”

In an interview with a Brazilian magazine, Jensen talks about directing an episode in season 6, and about where the season will pick up.

May 20: Variety announces Supernatural will air at 9pm on Fridays starting in September/October.

CW description of Supernatural's sixth season

When the Apocalypse was averted and Supernatural looked over the horizon of its original story arc, the decision by the creative team of showrunners Sera Gamble and Bob Singer along with creator Eric Kripke to take noir as the inspiration for season 6 seemed like a natural progression.