Vine growers supervise anti-frost candles burning between grapevines in a vineyard amid frosty temperatures in Weinboehla, Germany, April 26, 2021. REUTERS/Matthias Rietschel

Vine grower Till Neumeister lights an anti-frost candle between grapevines in a vineyard amid frosty temperatures in Weinboehla, Germany, April 26, 2021. REUTERS/Matthias Rietschel

Vine grower Till Neumeister lights an anti-frost candle between grapevines in a vineyard amid frosty temperatures in Weinboehla, Germany, April 26, 2021. REUTERS/Matthias Rietschel

Anti-frost candles burn between grapevines in a vineyard amid frosty temperatures in Weinboehla, Germany, April 26, 2021. REUTERS/Matthias Rietschel

Vine grower Till Neumeister lights an anti-frost candle between grapevines in a vineyard amid frosty temperatures in Weinboehla, Germany, April 26, 2021. REUTERS/Matthias Rietschel

Vine grower Hannes Maass lights an anti-frost candle between grapevines in a vineyard amid frosty temperatures in Weinboehla, Germany, April 26, 2021. REUTERS/Matthias Rietschel

Vine grower Hannes Maass lights an anti-frost candle between grapevines in a vineyard amid frosty temperatures in Weinboehla, Germany, April 26, 2021. REUTERS/Matthias Rietschel

Vine grower Till Neumeister lights an anti-frost candle between grapevines in a vineyard amid frosty temperatures in Weinboehla, Germany, April 26, 2021. REUTERS/Matthias Rietschel

The bud of a vine is seen as anti-frost candles burn between grapevines in a vineyard amid frosty temperatures in Weinboehla, Germany, April 26, 2021. REUTERS/Matthias Rietschel

Vine grower Till Neumeister supervises anti-frost candles between grapevines in a vineyard amid frosty temperatures in Weinboehla, Germany, April 26, 2021. REUTERS/Matthias Rietschel

Vine grower Till Neumeister lights anti-frost candles between grapevines in a vineyard amid frosty temperatures in Weinboehla, Germany, April 26, 2021. REUTERS/Matthias Rietschel

People gather at a bus stop on a frosty day in Bratsk in Irkutsk Region, Russia March 2, 2021. The sign reads: "Administration". REUTERS/Maxim Shemetov

Cars drive along a road near a timber processing plant on a frosty day in Bratsk in Irkutsk Region, Russia March 2, 2021. REUTERS/Maxim Shemetov

Smoke rises from the chimneys of houses on a frosty winter morning in the town of Tara in Omsk Region, Russia February 23, 2021. REUTERS/Alexey Malgavko

Smoke rises from the chimney of a house on a frosty winter day in the town of Tara in Omsk Region, Russia February 22, 2021. Picture taken February 22, 2021. REUTERS/Alexey Malgavko

Smoke rises from the chimneys of houses on a frosty winter day in Omsk, Russia February 22, 2021. Picture taken February 22, 2021. REUTERS/Alexey Malgavko

A passenger wearing a protective face mask sits inside a bus, amid the coronavirus disease (COVID-19), on a frosty winter day in central Kyiv, Ukraine February 16, 2021. REUTERS/Gleb Garanich

A woman wearing a protective face mask, amid the coronavirus disease (COVID-19) outbreak, walks past snowbanks along a street after snowfall on a frosty winter day, in central Kyiv, Ukraine February 16, 2021. REUTERS/Gleb Garanich

A woman wearing a protective face mask, amid the coronavirus disease (COVID-19) outbreak, walks past snowbanks along a street after snowfall on a frosty winter day, in central Kyiv, Ukraine February 16, 2021. REUTERS/Gleb Garanich

A general view of the Moscow State University building in a frosty fog during sunrise in Moscow, Russia February 15, 2021. REUTERS/Maxim Shemetov

Natalya Seraya, chairwoman of "Walruses of the Capital" winter swimming club, bathes in the icy waters of the Moskva River on a frosty day in Moscow, Russia February 13, 2021. REUTERS/Evgenia Novozhenina TPX IMAGES OF THE DAY

Natalya Seraya, chairwoman of "Walruses of the Capital" winter swimming club, swims in the icy waters of the Moskva River on a frosty day in Moscow, Russia February 13, 2021. REUTERS/Evgenia Novozhenina

A member of "Walruses of the Capital" winter swimming club bathes in the icy waters of the Moskva River on a frosty day in Moscow, Russia February 13, 2021. REUTERS/Evgenia Novozhenina

Members of "Walruses of the Capital" winter swimming club bathe in the icy waters of the Moskva River on a frosty day in Moscow, Russia February 13, 2021. REUTERS/Evgenia Novozhenina

Natalya Seraya, chairwoman of "Walruses of the Capital" winter swimming club, bathes in the icy waters of the Moskva River on a frosty day in Moscow, Russia February 13, 2021. REUTERS/Evgenia Novozhenina

Natalya Seraya, chairwoman of "Walruses of the Capital" winter swimming club, dives into the icy waters of the Moskva River on a frosty day in Moscow, Russia February 13, 2021. REUTERS/Evgenia Novozhenina

Natalya Seraya, chairwoman of "Walruses of the Capital" winter swimming club, dives into the icy waters of the Moskva River on a frosty day in Moscow, Russia February 13, 2021. REUTERS/Evgenia Novozhenina

A man skis in a forest on a frosty day in Moscow, Russia February 10, 2021. REUTERS/Evgenia Novozhenina

People use self-made exercise equipment while training in a forest on a frosty day in Moscow, Russia February 10, 2021. REUTERS/Evgenia Novozhenina

Steam from chimneys rises above residential buildings on a frosty day in Omsk, Russia January 24, 2021. REUTERS/Alexey Malgavko

A child sleds down a hill on a frosty winter day in Kyiv, Ukraine January 15, 2021 REUTERS/Valentyn Ogirenko

Children sled down a hill on a frosty winter day in Kyiv, Ukraine January 15, 2021 REUTERS/Valentyn Ogirenko

St.Basil’s Cathedral is seen during sunset on a frosty day in Moscow, Russia December 8, 2020. REUTERS/Maxim Shemetov

Sun sets behind the Moscow State University building on a frosty day in Moscow, Russia December 8, 2020. REUTERS/Maxim Shemetov

Towers of the State Historical Museum, St. Basil’s Cathedral and Stalin-era skyscraper are seen during sunset on a frosty day in Moscow, Russia December 8, 2020. REUTERS/Maxim Shemetov

Christ The Saviour Cathedral is seen during sunset on a frosty day in Moscow, Russia December 8, 2020. REUTERS/Maxim Shemetov

A tram rides along a street on a frosty day in Omsk, Russia November 23, 2020. REUTERS/Alexey Malgavko

Steam rises from chimneys of a thermal power plant and the Gazprom Neft's oil refinery on a frosty winter day in Omsk, Russia November 23, 2020. REUTERS/Alexey Malgavko

Steam rises from chimneys of a thermal power plant and the Gazprom Neft's oil refinery on a frosty winter day in Omsk, Russia November 23, 2020. REUTERS/Alexey Malgavko

A layer of frozen fog hangs above a field near a Tyendinaga Mohawk Territory camp at a railway crossing in Tyendinaga, Ontario, Canada February 14, 2020. Picture taken February 14, 2020. REUTERS/Chris Helgren

Small chunks of ice float on the water near Fournier Bay, Antarctica, February 3, 2020. REUTERS/Ueslei Marcelino SEARCH "ANTARCTICA PENGUINS" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

A general view of Moscow International Business Center, also known as "Moskva-City”, on a frosty day, in Russia February 8, 2020. REUTERS/Maxim Shemetov

Steam rises from chimneys of heating power plants on a frosty day in Moscow, Russia February 8, 2020. REUTERS/Maxim Shemetov

The sun sets behind apartment blocks on a frosty day in Moscow, Russia February 8, 2020. REUTERS/Maxim Shemetov

A view of the city centre during a sunset on a frosty day in Moscow, Russia February 8, 2020. REUTERS/Maxim Shemetov

A general view of Moscow International Business Center, also known as "Moskva-City”, on a frosty day, in Russia February 8, 2020. REUTERS/Maxim Shemetov

A general view of the city centre and steam rising from chimneys of a heating power plant on a frosty day in Moscow, Russia February 8, 2020. REUTERS/Maxim Shemetov

A general view of apartment blocks on a frosty day in Moscow, Russia February 8, 2020. REUTERS/Maxim Shemetov

Steam rises from chimneys of a heating power plant on a frosty day in Moscow, Russia February 8, 2020. REUTERS/Maxim Shemetov

A general view of Stalin-era skyscrapers and steam rising from chimneys of heating power plant on a frosty day in Moscow, Russia February 8, 2020. REUTERS/Maxim Shemetov

A small block of ice is displayed for a photo, close to Fournier Bay, Antarctica, February 3, 2020. Picture taken February 3, 2020. REUTERS/Ueslei Marcelino

A small block of ice is displayed for a photo, close to Fournier Bay, Antarctica, February 3, 2020. Picture taken February 3, 2020. REUTERS/Ueslei Marcelino

Vehicles drive along a road on a frosty day in Omsk, Russia January 31, 2020. REUTERS/Alexey Malgavko

Dogs are walked in the snow at Bannockburn, Scotland, Britain January 28, 2020. REUTERS/Russell Cheyne

A farmland is seen cover by snow near Nevada, Iowa, U.S., January 23, 2020. REUTERS/Carlos Barria TPX IMAGES OF THE DAY

A batting cage with a "No drugs" sign is seen in Des Moines, Iowa, U.S., January 23, 2020. REUTERS/Shannon Stapleton

Flags are placed on a street corner at Indianola, Iowa, Iowa, U.S., January 23, 2020. REUTERS/Ivan Alvarado

A helicopter flies over the ski resort during the 50th World Economic Forum (WEF) annual meeting in Davos, Switzerland, January 23, 2020. REUTERS/Denis Balibouse

A bird sits on a frozen river during a snowfall in Des Moines, Iowa, U.S., January 22, 2020. REUTERS/Ivan Alvarado

A mailbox sits on a snow covered road in Osage, Iowa, U.S., January 22, 2020. REUTERS/Shannon Stapleton