Commuters walk across London Bridge, as Tower Bridge adorned with the Olympic rings is seen behind them, on a wet, summer's morning July 6, 2012. (Andrew Winning/Reuters)

Less than three weeks before the start of the 2012 Olympics, British officials and athletes around the globe are bracing for a dark threat to the London Games: English weather.

In a city universally besmirched as climatically challenged and about which Jane Austen once wrote, “In London, it is always a sickly season,” early Olympics forecasts are cloudy, with a chance of chaos. As Britain copes with its wettest quarter since records began in 1910, officials have set up meteorological war rooms at the Olympic Park in East London as well as in other British host locations, including Eton and Weymouth.

Suggesting scenes of mud-caked Olympians ahead, torrential downpours already have wreaked havoc at recent British sporting events. Massive disruptions turned at least 10,000 spectators away from the Formula One race at Silverstone last week.

In June, areas across the nation experienced double the average rainfall, and July has brought flash floods that continue to turn roads into rivers and inundate homes and businesses in parts of the country. Extended forecasts suggest that while the bouts of heavy rain may abate, London weather could still be wetter than the already-moist average for much of the 2012 Games — testing years-in-the-making transit planning and potentially affecting the medal count.

Athletes, experts say, are competing at levels so high that every advantage counts, with inclement weather sometimes throwing even top competitors off their game. For example, Jesse Williams, the 2011 world champion in the high jump, struggled in the rain during Olympic qualifying and barely made the U.S. team. With a history of not performing his best in precipitation, Williams has shifted most of his training from Manhattan, Kan., where temperatures have topped 100 degrees, to Eugene, Ore., where the damp, temperate climate more closely mimics the conditions in London.

England’s soggy lead-up to Olympics (The Washington Post/Met Office, U.K.’s national weather service)

“He’s been challenged by inclement weather before, but he’s recognized what he’s likely to encounter in London, and he’s decided to train more in Oregon,” said Kansas State’s Cliff Rovelto, who coaches all three U.S. high jumpers. “It’s just one factor, one that’s been at the back of his mind.”

Others, meanwhile, are praying for rain. American Khadevis Robinson, competing in the 800 meters, said the wet weather has in the past proved to be a problem for Kenyan David Rudisha, the favorite.

“You know, he’s only lost twice in the last couple of years, both times in rain, which, by his own admission, is something he says is challenging for him,” Robinson said. “As an athlete, you use this to tell yourself, ‘Okay, maybe this gives me an opening, maybe this gives me a chance.’ Because it’s London, and you know it’s going to rain.”

London Olympics planners, acutely aware of the weather challenges, have gone to great lengths to minimize potential disruptions. They’ve planted special grass and built a filtration system into the equestrian courses, a move that could prevent a repeat of two recent events in the English countryside that were canceled because of heavy rains. Officials ordered a tailor-made cover for the BMX track in East London to ensure it keeps dry. Five sailing routes have been identified to cope with possible weather issues. Olympic Park will have five full-time meteorologists, with staffing 24 hours a day. And additional days of competition are being built into several sports — such as rowing and tennis — that could be affected by weather.

To be sure, weather plays a role at all Summer Olympics. In Athens in 2004, for instance, marathon runners had to practice at the crack of dawn to beat the intense heat. In London, the chance of rain is considered more of a factor than the relatively cool average highs of about 70 in August, which could end up aiding athletes in a number of sports.

Records and rain

Statistically speaking, London doesn’t quite live up to its reputation as the ultimate soggy city: Its average annual rainfall of 23.6 inches actually measures lower than that in Paris, New York or Washington. Rather, its rainy rap comes from frequently overcast skies that more often drizzle than pour buckets, with its fast-moving weather tending to push strong storms through the urban area relatively quickly.

But wetter, cooler weather has gripped London and the rest of England this summer for one of the same reasons that the U.S. East Coast is suffering intense heat waves: jet stream air currents lingering farther south than is normal this time of year. That could mean a less stifling start to this year’s Olympics than, say, the London Games of 1948, when temperatures soared into the 90s during the initial sunny days. But chills and rain kicked in later during those games, catching blame for soggy tracks that had the fewest world records broken of any modern Olympic Games.

Just as then, prolonged bouts of rain during this year’s Games could have an impact on the results, albeit one difficult to calculate. Experts cite the Wimbledon men’s final this past Sunday. The roof over Centre Court, closed because of rain, changed the environment of the match, appearing to give a further edge to Roger Federer over his British rival, Andy Murray.

Long-term forecasting is notoriously difficult, particularly in Britain. While warning that predictions could change, Charles Powell, spokesman at the Met Office — the country’s national weather service — said conditions during the Olympics should show at least some improvement over the past several weeks, but could still end up being wetter than average.

“The current 30-day forecast shows signs that yes, we will still get some more heavy rainfall and a few fine days — a mixed bag, really,” Powell said. “There is no clear signal that we’re going to have prolonged warm and sunny weather.”

Kenneth Andreasen, coach of the U.S. sailing team, said most of the top teams have been training in the windy English Channel for years. The U.S. team’s full-time meteorologist regularly monitors currents and weather patterns on the five Olympic courses off Weymouth.

At the Beijing Games in 2008, Andreasen said, sailors were prepared for calmer seas and lighter wind, planning early to run up flatter sails. But competition in Britain could be more challenging — and potentially more exciting — because of the trademark unpredictably and fast-moving nature of its island weather.

“In Weymouth, we’re going to have to be prepared for anything,” Andreasen said. “Could be cold and rainy or absolutely sunny skies. We’re just not going to know from one day to the next.”

A British mind-set

Assuming that the current patch of historically bad weather subsides, Debbie Jevans, director of sport for the London Organizing Committee, insisted that athletes should not face undue problems “and could even find our temperate climate pleasing.”

Foreign spectators, meanwhile, will need to adopt a British mind-set. During a river pageant on the Thames last month to mark Queen Elizabeth II’s 60 years on the throne, more than a million hardy Britons braved the relentless rain and gloom with nary a complaint.

“I remember being in Vancouver for the Winter Games, and as they said then, there is no such thing as bad weather, just bad clothing,” Jevans said. “Look, if it rains, just bring an umbrella.”

Yet despite all the planning, heavy rainfall could lead to frequent rescheduling of events and set up transit nightmares in London, where hundreds of thousands of visitors in town for the Games will already be testing the region’s roads and public transportation systems.

Nevertheless, with the rain out of anyone’s control, Danny Boyle, the British director hired to stage the opening ceremonies, has opted to surrender to it, even celebrate it. He has vowed that if Mother Nature does not sprinkle on London on July 27, he will — promising fake clouds with artificial rain. That British-style embrace of the weather stands in sharp contrast to the Beijing Games, when the Chinese hired 32,000 people, set up 26 control stations and shot dry ice into the clouds above Beijing National Stadium to “squeeze” any rain out of them ahead of the festivities.

“We’re going to have some rain in the stadium whether it rains or not,” Boyle told Britain’s ITV. “We can’t let people leave the opening ceremony without having a little bit of rain, even if it’s the most beautiful day on earth.”

Karla Adam contributed to this report.