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Hottest Day of Year in UK: Fans Swelter at Wimbledon, Commuters Face Train Delays

The mercury soared to a whopping 36.7 degrees Celsius on Wednesday at London Heathrow Airport, setting an all-time July record high for the United Kingdom.

Elsewhere in the U.K., temperatures in the mid-30s C were widespread on Wednesday, as a heat wave continued to bake Britain.

On Twitter, the hashtag ‘hottestdayoftheyear' was trending worldwide, as users tweeted their heat wave fashion, tips for staying cool and complaints about workplace air conditioners.

As Wimbledon continued under the blazing sun, organizers made the decision Wednesday to limit the number of spectators permitted into each match.

"We have reduced today's initial capacity slightly to 38,000 to allow people more room in the grounds and therefore more space in the shade and easier access to the free water points," a Wimbledon spokesman said.

"Assuming all is going well, we'll be letting more people in as the day progresses."

Close to 100 spectators sought medical attention on the first day of the competition, with roughly a third of those people reporting feeling faint amid the heat, according to the Independent.

On Tuesday, organizers agreed to permit 10-minute match breaks for female competitors upon request. According to Wimbledon's official website, the rule has been implemented only twice before, in 2006 and 2009.

Despite the conditions, officials did not close the roof on Centre Court, determining it would only be used if it was too dark to play without it.

Delays were mounting for commuters on National Rail lines Wednesday as soaring temperatures threatened to buckle the rails.

"Extremely high temperatures are forecast for today and because of this Network Rail will be introducing speed restrictions on various parts of the network, throughout the day," the organization said on its website.

First TransPennine Express began handing out ice lollies to commuters Wednesday in an effort to beat the heat.

The company also plans to hand out more than 18,000 water bottles to keep travelers hydrated.

Despite a brutal couple of days, relief from the oppressive heat is on the way.

"The U.K. will get some relief from the heat on Thursday as front moves through with some showers and thunderstorms," AccuWeather Meteorologist Eric Leister said.

Warmer weather is forecast to return again on Friday and Saturday, though it won't be as extreme as temperatures around the middle of the week.