Who would have thought it would rain in London of all places?

What began as a sunny start to day two of the Olympic tennis competitions at Wimbledon Centre Court was rained out by a heavy downpour, forcing athletes and spectators running to find cover as rain delayed the games by three hours.

The Olympic tennis matches were moved inside for the first time in 100 years, as the Center Court's retractable roof was forced to shield the games from the heavy rain. Ten matches were postponed because of the weather, including first-round doubles matches involving the 2008 gold medal teams, the Williams sisters and Roger Federer - Stanislas Wawrinka, reports The Associated Press.

The rain also forced delays at equestrian events held in Greenwich, south east London. The Daily Mail reports a ten-minute delay was enforced during the dressage event, which New Zealand's Andrew Nicholson called "an absolute disgrace."

"I thought the British were meant to be sporting people. I'm serious," he complained to The Daily Mail. "They didn't mind the thunder and the lightning and the rain earlier, and then suddenly it's a ten-minute delay. To me, the weather wasn't bad enough to warrant that, it's just a bit of rain isn't it? I'm very frustrated with the organisers, I'd expect more from them at an Olympic Games."

PHOTOS:

Loading Slideshow...

  • Caroline Wozniacki

    Caroline Wozniacki of Denmark looks on as a ball boy struggles to open an umbrella as rain interrupts play during a first round women's singles match against Tamira Paszek of Austria at the All England Lawn Tennis Championships at Wimbledon, England, Wednesday, June 27, 2012. (AP Photo/Kirsty Wigglesworth)

  • Donna Marshall, David Thorpe

    Donna Marshall and David Thorpe wait for the rain to stop at the All England Lawn Tennis Club at Wimbledon, in London, at the 2012 Summer Olympics, Sunday, July 29, 2012. (AP Photo/Mark Humphrey)

  • Fans wait for the rain to stop at the All England Lawn Tennis Club at Wimbledon, in London, at the 2012 Summer Olympics, Sunday, July 29, 2012. (AP Photo/Mark Humphrey)

  • People run for shelter during a rain storm at the All England Lawn Tennis Club at Wimbledon, in London, at the 2012 Summer Olympics, Sunday, July 29, 2012. (AP Photo/Mark Humphrey)

  • Mary Jenkins

    Mary Jenkins of Strabane, Northern Ireland, waits out a rain delay at the All England Lawn Tennis Club at Wimbledon, in London, at the 2012 Summer Olympics, Sunday, July 29, 2012. (AP Photo/Mark Humphrey)

  • FILE - In this July 6, 2012 file photo, spectators shelter under umbrellas as they watch Novak Djokovic of Serbia face Roger Federer of Switzerland in a men's semifinals match as rain delays play on the outer courts at the All England Lawn Tennis Championships at Wimbledon, England. Gold, silver, bronze: No matter who wins what at the London Olympics, a million or more visitors will need to get themselves an umbrella. (AP Photo/Alastair Grant, File)

  • Roger Federer

    Roger Federer of Switzerland walks off court as rain delays play during the men's final match against Andy Murray of Britain at the All England Lawn Tennis Championships at Wimbledon, England, Sunday, July 8, 2012. (AP Photo/Kirsty Wigglesworth)

  • Ground staff pull a cover as rain delays play during the women's final match between Serena Williams of the United States and Agnieszka Radwanska of Poland at the All England Lawn Tennis Championships at Wimbledon, England, Saturday, July 7, 2012. (AP Photo/Alastair Grant)

  • Andy Murray

    Andy Murray of Britain, center, looks at ground staff pulling a rain cover onto Centre Court as rain delays play during a quarterfinals match against David Ferrer of Spain at the All England Lawn Tennis Championships at Wimbledon, England, Wednesday, July 4, 2012. (AP Photo/Alastair Grant)

  • Petra Kvitova

    Petra Kvitova of the Czech Republic waits during a rain delay during a fourth round singles match against Francesca Schiavone of Italy at the All England Lawn Tennis Championships at Wimbledon, England, Monday, July 2, 2012. (AP Photo/Alastair Grant)

  • A worker sweeps water off a tarp covering a tennis court during a rain delay at the All England Lawn Tennis Club at Wimbledon, in London, at the 2012 Summer Olympics, Sunday, July 29, 2012. (AP Photo/Mark Humphrey)

  • Spectators wait in Number One court as they wait for play to resume between Andy Roddick of the United States and Jamie Baker of Britain after a brief rain shower at the All England Lawn Tennis Championships at Wimbledon, England, Wednesday, June 27, 2012. (AP Photo/Sang Tan)

  • Waiting out the rain...

    A spectator sits under an umbrella as rain delays play between Samantha Stosur of Australia and Arantxa Rus of Netherlands during a second round women's singles match at the All England Lawn Tennis Championships at Wimbledon, England, Wednesday, June 27, 2012. (AP Photo/Anja Niedringhaus)

  • A spectator covers her head from the rain with a British flag during the equestrian eventing dressage phase at Greenwich Park, at the 2012 Summer Olympics, Sunday, July 29, 2012, in London. (AP Photo/Markus Schreiber)

  • Marcelo Tosi

    Marcelo Tosi, of Brazil, tips his hat to the applauds of the crowd after competing with his horse Eleda All Black in the rain during the equestrian eventing dressage phase at the 2012 Summer Olympics, Sunday, July 29, 2012, in London. (AP Photo/David Goldman)

  • Niklas Lindback

    A judge calls for a ten minute delay during a rain downpour in the equestrian eventing dressage phase at the 2012 Summer Olympics, Sunday, July 29, 2012, in London. (AP Photo/David Goldman)

Also on HuffPost: