Temperatures in much of Europe are running 20 degrees or more above average as an early-season heat dome, a strong high-pressure system several miles up in the atmosphere that traps heat below, remains parked over the area. Monthly records have fallen in at least three countries as the region gets a taste of what could be another anomalously hot summer in store.
It’s the latest in a series of heat records that are disproportionately outpacing the occurrence of cold extremes, largely the product of a changing climate and a planet whose temperatures are skewed hot.
It comes at the same time as mild temperatures in Japan brought the earliest peak bloom to Kyoto’s cherry blossom trees in at least 1,200 years of bookkeeping. Record-high temperatures have extended to much of Asia, with another area of exceptional warmth concentrated in southern China.
On Wednesday, Germany and the Netherlands set all-time March records, reporting highs of 81 degrees (27.2 Celsius) and 79 degrees (26.1 Celsius), respectively. Kew Gardens, about 10 miles west of London on the River Thames, hit 76.1 degrees (24.5 Celsius) on Tuesday, the highest March temperature in Britain since 1968.
Climate historian Maximiliano Herrera has been tracking the records and their historical context, and he describes the episode as “historic.”
France also saw record warmth Tuesday as the nation’s average temperature was higher than on any other March day in recorded history. More than 220 weather stations, or roughly 37 percent of France’s network, observed new maximum March temperatures.
Jersey, the largest of the Channel Islands and just 10 miles off northern France, hit 73.2 degrees (22.9 Celsius) on Tuesday afternoon, the highest March temperature there in more than 125 years of records.
Guernsey, an island 15 miles to the northwest, hit 67.6 degrees (19.8 Celsius), its highest March temperature on record dating to 1843. The Guernsey Met Office is calling for near 68 degrees Thursday, but records are not in jeopardy because the calendar has flipped to April.
Alderney, Guernsey’s smaller sister island and the most northerly Channel Island, only made it to 54.1 degrees (12.3 Celsius) on Tuesday thanks to a strong northeasterly wind.
In Switzerland, monthly records fell at individual weather stations Tuesday, including some at high elevations of the Alps. That demonstrates just how deep, or how high off the ground, the warm air mass was, something to be expected with a large-scale heat dome. Grimsel, a mountain pass in south-central Switzerland, made it to 51.6 degrees (10.9 Celsius), surpassing the record of 50.7 degrees set on March 11, 1997. Chasseral, a roughly mile-high mountain peak in northwestern Switzerland, climbed to 57.2 degrees (14 Celsius), beating the record of 55.4 degrees set in March 1990.
Jersey smashes March temperature record !!
— Jersey Met (@Jersey_Met) March 30, 2021
The Maison St Louis observatory recorded its highest March air temperature since records began in 1894, with the value soaring to 22.9°C late this afternoon. pic.twitter.com/hyBZ3stFRt
Other stations in Switzerland beat records by two degrees or more, whereas typically records are broken only by a few tenths of a degree.
Belgium and Austria saw 13 and 29 stations, respectively, break local monthly records Tuesday, with records falling in Spain and Oman, as well. Belgium missed its national monthly record temperature Wednesday by just half a degree but set a March record for the national average temperature.
Wednesday also witnessed a new monthly record in Paris of 78.8 degrees (26 Celsius), beating the March 25, 1955, record by more than half a degree.
Meanwhile, France’s average maximum temperature Wednesday was the highest on record for March, hitting 85.6 degrees (29.8 Celsius) in the southwestern part of the country. And Luxembourg recorded its first 77-degree (25 Celsius) reading ever for March.
Farther east, India has been flirting with records, with temperatures rising above 114 degrees (45.6 Celsius) in spots as summer heat already builds. Hong Kong also recorded a number of records.
The heat in Europe is thanks to a dome of high pressure that has brought clear skies, sinking air and unusual warmth. The heat has been enough to expand columns of air vertically such that the “halfway” mark of the atmosphere is now about 656 feet (200 meters) higher than typical.
In the coming days, the heat dome over Europe will relinquish its grasp and dissipate some, while a new, even more formidable area of high pressure is forecast to become established over Iceland and northern Britain.
The late-March temperature records are the latest instance of anomalous warmth to hit Europe in recent years, fitting a pattern of more frequent and intense temperature extremes influenced by climate change. Much of Western Europe spent late February beneath an equally impressive heat dome with temperatures 25 degrees above normal.