Scores from yesterday's Compulsory Test and today's Freestyle decide the current standings.
The crowd really got involved with every test, hardly able to contain their enthusiasm until the end when, time after time, they burst into waves of spontaneous applause as the 20 Male, and 33 Female vaulters put on quite a show.
Wiegele, an industrial clerk from North Rhine-Westphalia who won the FEI Vaulting World Championship in 2006 and who is reigning German Champion, reversed the placings after yesterday's Female Compulsory Test when scoring 8.650 to take the lead ahead of Great Britain's Joanne Eccles today. Another of the German contingent, Antje Hill, lies third going into tomorrow's technical test.
Wiegele's performance was smooth and elegant, yet the 24-year-old displayed the strength required of the world's best vaulters. Eccles's test was technically excellent and also showed her power and body-control.
Wiegele said: "I made two mistakes, and if I hadn't made them it would have been even better. This is my first World Equestrian Games and I will never forget the atmosphere. The audience is absolutely great. The Games are super well organized. I always know exactly when everything is happening which is very good for competitors."
In the Male Freestyle, the Republic of South Africa's Kegan Smith set the arena alight with a flamboyant display that stood out from the rest. He travelled to the the USA four weeks ago, and based himself in Colorado as he put in his final preparations ahead of the big event. And with his 18.2hh horse, Smokin Joe, he ensured he couldn't be missed today as he performed to the theme tune of the Mel Brooke's movie "Men in Tights", dressed as Robin Hood.
At the sharp end of the leaderboard, Patric Looser took the lead with a new routine that was very technically correct. He is now ahead of French vaulter Nicolas Andreani, while 2006 World Champion Kai Vorberg is third and fellow-German and first-day leader Gero Meyer is in fourth place.
Ling Yang, first Chinese vaulter to compete at the FEI World Equestrian Games, said the event was unbelievable. "It's the best experience ever in my lifetime. I've met so many very friendly people."
33 competed in the Female Individual Freestyle today.
20 competed in the Male Individual Freestyle today.
Today's scores are the combined results from the first two days of competition.
Female Individual: 1, Simone Wiegele GER 8.344; 2, Joanne Eccles GBR 8.274; 3, Antje Hill GER 8.121.
Male Individual: 1, Patric Looser (SUI) 8.524; 2, Nicolas Andreani FRA 8.405; 3, Kai Vorberg GER 8.366.