High Quality Content by WIKIPEDIA articles! The 2013 WTA Tour is the elite professional tennis circuit organized by the Women`s Tennis Association (WTA) for the 2013 tennis season. The 2013 WTA Tour calendar comprises the Grand Slam tournaments (supervised by the International Tennis Federation (ITF)), the WTA Premier tournaments (Premier Mandatory, Premier 5, and regular Premier), the WTA International tournaments, the Fed Cup (organized by the ITF) and the year-end championships (the WTA Tour Championships and the WTA Tournament of Champions).