Valley fog, caused by cool air flowing over moist land, drifts across Oxford County in this view at dawn looking east over Lovell, Maine, Friday, September 8, 2017. (Photo by Robert F. Bukaty/AP Photo)





This July 22, 2017 photo taken with long time exposure shows lightnings during thunderstorms near the highway 661 in Oberursel, near Frankfurt, Germany. (Photo by Jan Eifert/DPA via AP Photo)





Storm front sweeping up the NSW coast on January 9, 2018 in Sydney, Australia. Heavy wind, rain and severe hailstorms are expected throughout eastern New South Wales. (Photo by Michele Mossop/Getty Images)





The silhouette of Japan's highest mountain Mount Fuji is seen beyond buildings in the dusk in Tokyo, Japan September 12, 2017. (Photo by Issei Kato/Reuters)





Cloud patterns converge above the East Park Skate Park in Bremerton, Wash., on Wednesday, December 13, 2017. A rare fallstreak hole is in the middle. (Photo by Larry Steagall/Kitsap Sun via AP Photo)





The sun sets behind La Corbiere lighthouse in Jersey, Britain November 8, 2017. (Photo by Darren Staples/Reuters)





A tree is seen in Val D'Orcia, Italy, January 5, 2018. (Photo by Max Rossi/Reuters)





Power-generating wind turbines are seen at a wind park near Greneville-en-Beauce, France, November 30, 2017. (Photo by Christian Hartmann/Reuters)





A Qatar Airways Boeing jet, flying from Sao Paulo, Brazil to Doha, Qatar, is seen at sunset from the island of Gozo, Malta on January 25, 2018. (Photo by Darrin Zammit Lupi/Reuters)





Trees are pictured at sunrise in Tula region, Russia January 26, 2018. (Photo by Maxim Shemetov/Reuters)





In this Wednesday, August 9, 2017 photo unsettled clouds fill the sky over Mount Katahdin in this view from Patten, Maine. Interior Secretary Ryan Zinke wants to retain the newly created Katahdin Woods and Waters National Monument in northern Maine, but said he might recommend adjustments to the White House on Thursday, Aug. 24, 2017. (Photo by Robert F. Bukaty/AP Photo)





A Palestinian fishing boat sails as the sun sets on the coast off Gaza City, Sunday, March 18, 2018. (Photo by Khalil Hamra/AP Photo)





The setting sun lights the evening sky behind the mountains west of Denver late Thursday, June 29, 2017. Forecasters predict that the warm weather will relent on Friday before the heat returns over the Fourth of July holiday, sending temperatures into the mid-90s. (Photo by David Zalubowski/AP Photo)





Bikers compete in a qualifying session of the 81st Bol d'Or 24-hour motorbike endurance race, on September 14, 2017, at the Paul Ricard racetrack in Le Castellet, southern France. (Photo by Boris Horvat/AFP Photo)





The sunsets over a lone tree on a ridge in Bears Ears National Monument June 10, 2017 near Moab, UT. (Photo by Katherine Frey/The Washington Post)





Washington National Cathedral is seen during sunset after a storm this afternoon on Monday, June 19, 2017, in Washington, D.C. (Photo by Salwan Georges/The Washington Post)





A Southwest Airlines jet takes off from Reagan National Airport with a thunderhead to the east on June 20, 2017 in Alexandria, VA. (Photo by Jonathan Newton/The Washington Post)





A colourful sunset in Milan, Italy on October 29, 2017. (Photo by Daniel Dal Zennaro/EPA/EFE/Rex Features/Shutterstock)