LONDON — The United Kingdom recorded its hottest day ever on Thursday in a heat wave that also shattered temperature records in France, the Netherlands and Belgium.

Temperatures reached 101.66 degrees at Cambridge University Botanic Garden, according to new provisional data released by the U.K.'s Met Office on Friday. If verified, it would make Thursday the hottest day ever on record in the country. The country's previous record high of 101.3 degrees was set in 2003.

Paris also reached a stunning 105 degrees at 1:36 p.m. local time, according to the French meteorological agency Météo-France.

The Royal Netherland Meteorological Institute said the country saw its hottest day ever, reaching 104 degrees at the Gilze-Rijen airbase in the southern part of the country. Belgium's head forecaster for its national meteorological agency David Dehenauw said the Kleine Brogel air base, roughly 55 miles east of Antwerp, broke national records reaching 105 degrees.

As Britons endured delayed trains, suffocating subways and baking homes, the U.K.'s Met Office said the mercury hit 98.4 degrees at London's Heathrow Airport before 2 p.m. local time, making it the country's hottest day ever for the month of July.

Although the sky-high temperatures were expected to be short-lived with rain forecast to bring reprieve to Britain on Friday, experts warn that extreme heat has become the new normal with climate change. The past four years were the hottest on record globally and the World Meteorological Organization has warned this year is expected to be the same.

A report released Thursday by the U.K.-based Chartered Institute of Water and Environmental Management found that while Britain has progressed on commitments to reduce emissions, plans to adapt to climate change are sorely lacking. It reiterated similar findings by the government's committee on climate change released earlier in the month.

Infrastructure, such as roads and housing, and emergency planning and response need to catch up with the current and future challenges posed by extreme weather, the report said.

Southeastern Railway, which covers areas most impacted by Thursday’s heat in England, warned there would be reduced service. Metal tracks risk buckling in temperatures above 122 degrees, the railway said, requiring speed restrictions to be enforced to maintain safety.

Last year, disruptions to network rail in Britain due to heat resulted in losses in the range of £40 million ($50 million) for operators, Alastair Chisholm, director of policy at the institute, told NBC News.

The bulk of housing in Britain wasn't designed to acclimate to such high temperatures and often lacks central air conditioning. Government programs incentivizing upgrades to home insulation, for example, have largely disappeared in recent years due to austerity measures, Chisholm said.

It was no surprise that U.K. retailer Argos saw a spike in sales for summer-related housewares. Sales of ice cream makers were up 62 percent compared with last year while sales for paddling pools were up 400 percent week over week, the company said.

Wednesday saw highest-ever sales of fans with 95,000 units purchased, the company added.

The rest of Europe faces similar concerns about homes and buildings being ill-prepared for the new reality of summer heat.

Architect Philippe Villeneuve said he’s worried this week's high temperatures could further damage the Notre Dame cathedral that was charred in a fire earlier this year.

Villneuve explained that the stone walls that were exposed to flames then saturated with water by firefighters could now dry out rapidly, causing the vaulted ceilings to become unstable and collapse.

These problems not only pose technical challenges and individual inconveniences but also have wider effects on the economy.

"We know when people are too hot they become less productive, so even if they make it in to work with the infrastructure not working as it should, they might be less productive," said Bob Ward, director of policy and communications for the Grantham Research Institute on Climate Change and the Environment.

Urban centers like London can also be "doubly lethal," Ward explained, because the cement buildings and roads absorb more heat, driving temperatures up. The bright sunshine reflecting off infrastructure also results in a chemical reaction that worsens air pollution, putting people with respiratory problems at greater risk, he said.

If the financial implications of the heat waves weren't incentive enough for cities and countries to adapt, Ward added, "I hope that risk to people's lives is the primary driver."

Extreme heat has proven to be deadly. In 2003, a heat wave resulted in more than 50,000 deaths across Europe.

Last year, Britain saw more than 800 people die in connection with four extreme heat events throughout the summer, Ward said.

"It might be worth for us to consider giving heat waves names as we started to give winter storms names," he suggested. "It's about recognizing heat waves as potential public health emergencies."