In the coastal Spanish town of San Sebastián, residents swapped coats for T-shirts and headed to the beach for a swim. In Rome, tourists and locals strolled in the sunshine in light sweaters. And in low-lying areas of the Pyrenees, a lack of snowfall forced some French ski resorts to close trails.
An unusually warm start to January broke dozens of weather records across Europe. Meteorologists called the warm spell and the records it broke “staggering,” as several countries saw the hottest start to the year ever measured.
In Brest, Belarus, for example, temperatures usually hover around freezing, but on New Year’s Day they hit a record 60.6 degrees Fahrenheit, or 15.9 Celsius. Temperatures in the Czech Republic on Monday, according to the national meteorology office, matched or broke records going back at least 30 years at 90 of 162 stations in the nation.
Residents in Warsaw enjoyed the balmiest start to the year since 1999, with a high of 66 degrees Fahrenheit. Latvia, Lithuania and the Netherlands also experienced record warmth on New Year’s Day. France recorded the warmest winter night since 1947 just before the new year, said Météo France, the country’s national forecaster.
Though temperatures have cooled in the past days in some areas, the unseasonal warmth capped a year of already historic highs, with Britain, France and Spain announcing that 2022 was expected to be the hottest year on record following a summer of heat waves.
While tying a single heat wave or warm spell to climate change requires analysis, it is clear that global warming is causing heat waves around the world to become hotter, more frequent and longer lasting.
“The record-breaking heat across Europe over the new year was made more likely to happen by human-caused climate change, just as climate change is now making every heat wave more likely and hotter,” said Dr. Friederike Otto, senior lecturer at the Grantham Institute — Climate Change and Environment at Imperial College London, in a statement. “As long as greenhouse gas emissions continue, heat waves like these will become increasingly common and severe.”
Despite being a balmy break from the wintry chill, the uncharacteristic warmth disrupted some seasonal activities and left many disconcerted.
It forced some ski resorts in low-lying mountain ranges like the Pyrenees and the Vosges to close trails during their peak season. At mid-altitude resorts in the Northern Alps, said Robert Vautard, a scientist and a coordinating lead author for the United Nations Intergovernmental Panel on Climate Change, it rained, instead of the usual snow at Christmas. “You have grass, you have no snow,” he said. “It’s clearly unusual but it’s not unprecedented.”
In Switzerland, where temperatures hit a record 68 degrees, north of the Alps on New Year’s Day the Swiss resort of Adelboden-Lenk, which will host a skiing World Cup event next weekend, brought in artificial snow.
“This winter is being like summer, suffocating,” said Josu Cires, 52. On Wednesday he was driving to his job selling beer in the city of Bilbao in northern Spain, which has seen temperatures above 77 degrees — more typical of July than January. Mr. Cires said that he was struggling with the heat. “The landscape is beautiful, but the body suffers.”
The unusual heat in Spain’s Basque Country, normally one of the country’s rainiest areas, prompted its regional government on New Year’s Day to issue an emergency alert, citing risk of forest fires.
In Germany, one headline proclaimed, “T-shirt weather on New Year’s Eve in Bavaria.” In a normal year, visitors to the region’s Christmas markets fight off the cold with mulled wine. In Munich, the temperature on New Year’s Eve was above 68 degrees, the highest ever measured on that date.
A fast-moving, warm air mass from the Tropical Atlantic moved toward Western and Central Europe, prompting the unusual heat, said Mr. Vautard, adding that the system also drew heat from the ocean, which is warming from absorbing the heat trapped by greenhouse gases that humans dump into the atmosphere. “Everything is warmer, the ocean is warmer and therefore all the air coming from the ocean is warmer.”
“It’s completely exceptional at this time of year,” he added. “It’s what we used to call record-shattering extremes.”
Britain has also experienced milder than usual temperatures, with a record 61 degrees recorded in London on New Year’s Day, according to its Met Office.
“The temperatures observed in Europe are staggering,” Scott Duncan, a meteorologist based in London who was monitoring the temperature increases, said in an email. “We observed longstanding records broken by large margins across several countries.”
The warmer temperatures in Europe come after Arctic air blanketed the United States last month, bringing in subzero temperatures and a deadly blizzard that buried parts of the country. It was possible there was a “weak to medium” connection between the that storm and the warm weather in Europe said Mr. Vautard.
“It’s quite usual that when it’s getting cold in the U.S., we get warm temperatures and vice versa,” he said, adding that the storm that moved through the United States dragged air from the Gulf of Mexico to the Atlantic, where it mixed with other air masses, and that the atmosphere was turbulent at this time of the year. “Things can get chaotic,” he said.
Reporting was contributed by Aurelien Breeden in Paris, Christopher F. Schuetze in Berlin, Emma Bubola in Rome, and José Bautista in Madrid.