Pedestrians walk in front of a placard advertising a soon-to-open shop in Regent street, central London on August 17, 2016 Retail sales in Britain, a key driver of the country's economy, rebounded 1.4 percent in July from the previous month's drop, official data showed on August 18, calming fears over any immediate fallout from Brexit. Sales by volume rose sharply following a 0.9-percent drop in June that had been caused by wet summer weather, according to the Office for National Statistics. / AFP PHOTO / DANIEL LEAL-OLIVASDANIEL LEAL-OLIVAS/AFP/Getty Images

RIO DE JANEIRO, BRAZIL - AUGUST 17: Women's 470 Women's competition is postponed for the day due to weather on Day 12 of the Rio 2016 Olympic Games at Marina da Gloria on August 17, 2016 in Rio de Janeiro, Brazil. (Photo by Paul Gilham/Getty Images)

(FILES) This file photo taken on August 12, 2016 shows a woman as she shades herself from the sun with an umbrella as she walks on the National Mall during warm weather in Washington, DC. July marked the Earth's hottest month in modern times, setting a new record for planet-wide heat that has not been seen in 137 years of record-keeping, US government scientists said August 17, 2016."The globally averaged temperature over land and ocean surfaces for July 2016 was the highest for both the month of July and for any month in the NOAA global temperature dataset record, which dates back to 1880," said the National Oceanic and Atmospheric Administration. / AFP PHOTO / Brendan SmialowskiBRENDAN SMIALOWSKI/AFP/Getty Images

GLENRIDDING, ENGLAND - AUGUST 17: Sail boats on Ullswater enjoy the fine weather on August 17, 2016 in Glenridding, England. The Lake District continues to recover after the devastating Storm Desmond hit the region in December last year. Many bridges and roads have been fully repaired but some homes and businesses are still being rebuilt. The recent fine weather has seen tousrists flock to see the natural beauty of the hills and dales. The Lake district is Britains most visited national park with tourists arriving from around the world for its lakes, valleys, woodlands and fells. (Photo by Christopher Furlong/Getty Images)

GLENRIDDING, ENGLAND - AUGUST 17: Sail boats on Ullswater enjoy the fine weather on August 17, 2016 in Glenridding, England. The Lake District continues to recover after the devastating Storm Desmond hit the region in December last year. Many bridges and roads have been fully repaired but some homes and businesses are still being rebuilt. The recent fine weather has seen tousrists flock to see the natural beauty of the hills and dales. The Lake district is Britains most visited national park with tourists arriving from around the world for its lakes, valleys, woodlands and fells. (Photo by Christopher Furlong/Getty Images)

KESWICK, ENGLAND - AUGUST 17: People queue for a pleasure boat ride on Derwent Water on August 17, 2016 in Keswick, England. The Lake District continues to recover after the devastating Storm Desmond hit the region in December last year. Many bridges and roads have been fully repaired but some homes and businesses are still being rebuilt. The recent fine weather has seen tousrists flock to see the natural beauty of the hills and dales. The Lake district is Britains most visited national park with tourists arriving from around the world for its lakes, valleys, woodlands and fells. (Photo by Christopher Furlong/Getty Images)

KESWICK, ENGLAND - AUGUST 17: People enjoy a paddle to cool off in Derwent Water on August 17, 2016 in Keswick, England. The Lake District continues to recover after the devastating Storm Desmond hit the region in December last year. Many bridges and roads have been fully repaired but some homes and businesses are still being rebuilt. The recent fine weather has seen tousrists flock to see the natural beauty of the hills and dales. The Lake district is Britains most visited national park with tourists arriving from around the world for its lakes, valleys, woodlands and fells. (Photo by Christopher Furlong/Getty Images)

GLENRIDDING, ENGLAND - AUGUST 17: Businesses and hotels continue to be repaired after damage by Storm Desmond on August 17, 2016 in Glenridding, England. The Lake District continues to recover after the devastating Storm Desmond hit the region in December last year. Many bridges and roads have been fully repaired but some homes and businesses are still being rebuilt. The recent fine weather has seen tousrists flock to see the natural beauty of the hills and dales. The Lake district is Britains most visited national park with tourists arriving from around the world for its lakes, valleys, woodlands and fells. (Photo by Christopher Furlong/Getty Images)