Originally Published:  July 1, 2012
Updated:  December 4, 2018

This should be pretty self-explanatory:  a list of dates of the major events in Seattle Sonics history.  I plan to add to this as new events happen.  I also plan to fill it out as I learn more about the history.

December 20, 1966 – NBA awards Seattle with an expansion franchise.
October 13, 1967 – Seattle Supersonics play their first regular season game, lose @ San Francisco Warriors 144-116.
October 20, 1967 – Supersonics play their first home game, in Seattle Center Coliseum, lose to San Diego Rockets 121-114.  Total crowd:  4,473.
October 21, 1967 – Supersonics win their first game, @ San Diego Rockets 117-110 (OT).
October 12, 1968 – Supersonics trade Walt Hazzard to Atlanta Hawks for Lenny Wilkens.

December 30, 1970 – Supersonics sign Spencer Haywood to a 6-year, $1.5 million contract.
March 1, 1971 – U.S. Supreme Court rules in favor of Spencer Haywood and the Sonics, allowing him to play in the NBA without waiting 4 years from high school graduation.
March 29, 1971 – Supersonics draft Downtown Freddie Brown with 6th overall pick.
March 26, 1972 – Supersonics finish regular season with first-ever winning record (47-35).
August 23, 1972 – Supersonics trade Lenny Wilkens & Barry Clemens to Cleveland Cavaliers for Butch Beard.
May 11, 1973 – Supersonics sign Bill Russell as head coach & general manager.
January 15, 1974 – Seattle hosts its first All-Star Game at the Coliseum.
April 8, 1975 – Supersonics play in first-ever playoff game, defeating Detroit Pistons at home 90-77.
October 24, 1975 – Supersonics trade Spencer Haywood to New York Knicks for Gene Short & a 1979 1st round pick which turns into James Bailey.
June 10, 1977 – Supersonics draft Jack Sikma with the 8th overall pick.
October 17, 1977 – Supersonics sign Gus Williams as a veteran free agent.
November 30, 1977 – 5-17 Supersonics fire head coach Bob Hopkins & re-hire Lenny Wilkens.
May 21, 1978 – Supersonics play in first-ever NBA Finals game, defeat Washington Bullets at home 106-102.
June 4, 1978 – Supersonics lose NBA Finals to Washington Bullets in 6 games, 117-82.
October 13, 1978 – Supersonics move from Coliseum to Kingdome.
June 1, 1979 – Supersonics win NBA Title over Washington Bullets in 5 games, 97-93.

October 15, 1983 – Supersonics sold to Barry Ackerley for $13 million.
January 5, 1986 – Supersonics, back in the Coliseum, host a rained-out game due to a leaky roof.
June 17, 1986 – Supersonics draft Nate McMillan with the 30th overall pick.
July 1, 1986 – Supersonics trade Jack Sikma with picks to Milwaukee Bucks for Alton Lister and picks.
February 8, 1987 – Seattle hosts All-Star Game at Kingdome.  Tom Chambers scores 34 points to win the MVP.
June 22, 1987 – Supersonics draft Scottie Pippen with the 5th overall pick, trade him to Chicago Bulls for Olden Polynice.
June 27, 1989 – Supersonics draft Shawn Kemp with the 17th overall pick.

June 17, 1990 – Supersonics draft Gary Payton with the 2nd overall pick.
January 23, 1992 – Supersonics hire George Karl as head coach.
November 1, 1993 – Supersonics trade Derrick McKey & Gerald Paddio to Indiana Pacers for Detlef Schrempf.
February 4, 1994 – Supersonics sign 15-year lease & City Council approves sale of $73.4 million in bonds for renovation of Coliseum.
May 7, 1994 – Supersonics lose in first round to Denver Nuggets 98-94 (OT), become first-ever #1 Seed to lose to a #8 Seed.
June 16, 1994 – Construction begins to renovate Coliseum.
November 4, 1995 – Supersonics play their first game at Key Arena, defeat L.A. Lakers 103-89.
June 2, 1996 – Supersonics defeat Utah Jazz in Game 7 of the Western Conference Finals at home 90-86.
June 16, 1996 – Supersonics lose NBA Finals to Chicago Bulls in 6 games, 87-75.
July 22, 1996 – Supersonics sign Jim McIlvaine to a 7-year, $33.6 Million deal.
June 5, 1997 – Shawn Kemp demands trade from Seattle.
September 25, 1997 – Supersonics trade Shawn Kemp to Cleveland Cavaliers in 3-team deal.  Seattle receives in return Vin Baker from Milwaukee Bucks.
May 26, 1998 – Supersonics hire Paul Westphal as head coach.

November 27, 2000 – Supersonics name Nate McMillan as interim head coach.
January 11, 2001 – Supersonics sold to Howard Schultz for $200 million.
February 20, 2003 – Supersonics trade Gary Payton to Milwaukee Bucks with Desmond Mason for Ray Allen, Flip Murray, Kevin Ollie, & a 2003 1st round pick which turns into Luke Ridnour.
April 20, 2005 – Supersonics finish season in first in the Northwest Division with a 52-30 record.  It would be the team’s final winning season and playoff appearance.
July 6, 2005 – Supersonics allow Nate McMillan to sign as head coach of Portland Trailblazers.
July 18, 2005 – Supersonics promote Bob Weiss to head coach.
January 3, 2006 – Supersonics name Bob Hill their head coach.
July 18, 2006 – Supersonics sold to Clay Bennett for $350 million.
November 7, 2006 – Seattle voters approve I-91 which severely restricts city tax subsidies for pro sports teams.
February 12, 2007 – Clay Bennett reveals $500 million Renton Arena proposal.
April 16, 2007 – State legislature rejects Supersonics’ proposal to build a $500 million arena in Renton with extension of taxes being used to pay off Safeco & Qwest Fields.
June 7, 2007 – Supersonics hire Sam Presti as General Manager.
June 28, 2007 – Supersonics draft Kevin Durant with the 2nd overall pick.
July 5, 2007 – Supersonics hire P.J. Carlesimo as head coach.
August 13, 2007 – Aubrey McClendon tells Oklahoma City Journal Record of their group’s intentions:  that they were planning all along to move the team to OKC.
September 10, 2007 – Seattle City Council votes 8-0 to strictly enforce Key Arena lease signed in 1994.
September 21, 2007 – Supersonics owners file for arbitration on Key Arena, seeking approval to pay a cash settlement instead of playing out the final two years of the lease.
September 24, 2007 – Seattle files a lawsuit to hold Supersonics to their lease through 2010.
November 2, 2007 – Clay Bennett announces he is seeking NBA permission to move the Supersonics to OKC.
January 8, 2008 – Clay Bennett sells the Storm so they can remain in Seattle.
March 6, 2008 – Steve Ballmer proposes $300 million renovation project of Key Arena, of which he promises to pay half.
April 10, 2008 – Deadline passes for state legislature to accept Steve Ballmer’s proposal.
April 13, 2008 – Supersonics play their final game in Seattle, defeating Dallas Mavericks 99-95.
April 16, 2008 – Supersonics play their final game, defeating Golden State Warriors 126-121.
April 18, 2008 – NBA approves Supersonics’ move to OKC.
June 16, 2008 – First day of testimony for trial to settle Supersonics’ lease issue with Seattle.
July 2, 2008 – Hours before U.S. District Court Judge Marsha Pechman was to give her ruling, Supersonics reach an agreement with Seattle, buying out final two years of its lease at Key Arena for $45 million.  Agreement dictates OKC cannot use name or colors (to be reserved for a new team in Seattle), but will share Supersonics’ history.
August 18, 2009 – Seattle Mayor Greg Nickels finishes third in primary for Seattle mayoral election, ineligible to run in the general election.

February 4, 2012 – Seattle Times breaks the story that a hedge-fund manager by the name of Chris Hansen is working with Seattle city officials on a proposed arena deal.
February 16, 2012 – Officials announce arena proposal for SoDo area, led by Chris Hansen as primary investor.
June 13, 2012 – Chris Hansen announces other investors, including Steve Ballmer & Erik & Pete Nordstrom.
June 14, 2012 – Rally for arena deal takes place at Occidental Park.
July 26, 2012 – Don Levin makes public his intention to build an arena in Bellevue & bring in an NHL franchise.  Such an arena would also, ideally, house an NBA franchise as well.
July 30, 2012 – King County Council passes MOU 6-3.  Seattle City Council has more demands.
September 11, 2012 – Chris Hansen reaches deal with Seattle City Council.  Vote to happen later this week.
September 24, 2012 – City of Seattle votes to approve MOU, 6-2.
October 15, 2012 – Final vote.  Both City of Seattle & King County pass arena deal.  Chris Hansen can now go find a team.
January 21, 2013 – Hansen’s group announces purchase of majority stake of Sacramento Kings.  As this falls prior to March 1st deadline, pending approval by Board of Governors, the Seattle Sonics could return to Key Arena for 2013/2014 season.  Sacramento mayor Kevin Johnson still has time to find buyers and arrange for an arena deal to keep team in Sacramento.
February 6, 2013 – Chris Hansen files with the NBA to relocate the Kings to Seattle for the 2013/2014 season.
April 12, 2013 – Seattle group officially increases its bid from $525 million to $550 million.
April 29, 2013 – NBA Relocation Committee votes to recommend rejecting the move of the Kings to Seattle.
May 10, 2013 – Seattle group officially increases its bid from $550 million to $625 million.  Sacramento group appears unwilling to match offer; has its offer firm at $525 million.
May 11, 2013 – Seattle group & Maloofs reach backup deal to sell 20% stake for $125 million if the NBA rejects bid to relocate to Seattle.  Maloofs would then continue to run the team, have vowed to not sell to Sacramento group.
May 15, 2013 – NBA Board of Governors vote 22-8 to reject relocation of Kings to Seattle, effectively voiding Hansen & Ballmer’s deal to purchase 65% of the team.  Commissioner states expansion is a possibility, but not until the NBA re-works its national television deal, which expires after the 2015/2016 season.  Reports indicate the NBA is looking to start discussions this summer, with a formal deal expected sometime in 2014.
August 12, 2014 – Steve Ballmer officially becomes owner of the L.A. Clippers.
May 2, 2016 – Seattle City Council votes 5-4 against allowing a street vacation for Occidental Avenue, in the hypothetical scenario where an arena would be built in SoDo.  A vote in favor would’ve made Seattle “shovel-ready” in a scenario where a team became available.  Instead, more work needs to be done (at best) or the deal is effectively dead (at worst).
April 12, 2017 – Deadline for the three groups to submit their arena proposals to the city.  The Oak View Group (led by Tim Leiweke) and AEG are both working to renovate Key Arena, while Chris Hansen’s group (now featuring the likes of Russell Wilson, presumably to build more local support) is still trying to get his street vacation for Occidental Avenue.  Now, Hansen’s project is going to be 100% privately funded, on top of shelling out millions of dollars to help with SoDo street projects in the area.  A decision on which proposal the city will back is expected in the summer sometime.
June 7, 2017 – Mayor Ed Murray has put his support behind the Oak View Group, as AEG backed out in recent days.  The plan is for an MOU to be finalized by the end of the year.  Major hockey backers are joining this group, including David Bonderman and Jerry Bruckheimer, which seems to favor the NHL coming to Seattle prior to the NBA.  Likewise, with the city anticipated to throw all its support behind a renovated Key Arena, this appears to effectively kill Chris Hansen’s SoDo Arena ambitions (though, the City Council still has to officially re-vote on the Occidental Avenue street vacation).
December 3, 2017 – Chris Hansen’s SoDo Arena MOU expires, without a re-vote on the street vacation.
December 4, 2017 – Seattle City Council votes 7-1 to approve MOU with Oak View Group to renovate Key Arena.
December 4, 2018 – NHL votes unanimously to approve expansion hockey team to Seattle, starting in 2021.