For many in the eastern and central U.S., the summer of 2013 has felt temperate – if not cool – after record heat in recent years. Those wondering where it’s been hot this summer need only look across the Atlantic.
Much of Europe sweated through its hottest July since 2006, and a resurgence of heat this week pushed temperatures up to 40 C (104 F) in Austria, Hungary, and Poland.
Austria set a new national high temperature record Thursday when the mercury climbed to 40.5ºC (104.9ºF) in Bad Deutsch-Altenburg, a town near the Slovakian border. The Austrian meteorological service ZAMG reports two other locations recorded readings at or above 40 C on August 8, making it the first time the country has ever eclipsed the 40 C mark since daily records began in 1858.
Initial reports had suggested an even higher temperature of 40.6 C (105.1 F) recorded at Neusiedl am See, but ZAMG declared it invalid after finding inconsistencies in the reading.
Just last week, Austria had recorded a new all-time high of 39.9 C (103.8 F) in Dellach, Carinthia on August 3. Prior to 2013, the country’s old high temperature record was 39.7 C (103.4 F) set in the same location on July 27, 1983.
Alongside the national record, Thursday broke several provincial high temperature records throughout Austria, including 39.5 C (103.1 F) in Vienna. It was the warmest temperature ever recorded in the Austrian capital, and broke the city’s previous all-time high of 38.9 C (102 F) from July 8, 1957. This week’s heat comes after numerous heat records were shattered last month, which was Austria’s second warmest July on record.
Extreme heat has also gripped neighboring countries, stretching from Poland and the Czech Republic southward into the Balkans.
In Budapest, the thermometer fell shy of the 40 C mark, but may have still broken its all-time heat record of 39.4 C, writes Christopher Burt from Wunderground. And farther south, Slovenia also broke its national high temperature record, as well as an all-time high in the capital, Ljubljana. The city reportedly broke its old heat record five times in the same week, as a maximum of 40.2 C (104.4 F) replaced the old record of 38.0 C (100.4 F) from 1935.
Western Europe: Less hot but July near warmest on record
While the epicenter of Europe’s heat wave has been centered on Austria and Hungary, very warm weather also dominated the second half of July in Germany, France, and the UK.
In Germany, late July brought widespread temperatures above 30 C (86 F), with the hottest regions eclipsing 35 C (95 F) in Bavaria and the northern Alps. Though temperatures fell shy of all-time records, last month was Germany’s 6th warmest July since records began. Only five other Julys were hotter: 2006, 1994, 1983, 2010, and 1995.
Closer to the Atlantic, both France and the UK recorded their 3rd warmest July on record, with temperatures averaging about 2ºC above the 1981-2010 normal. Only 2006 and 1983 were hotter – though unlike central Europe, neither country set any new July temperature records. (The French weather service offers a nice visual comparison of how last month’s heat wave compared historically in both intensity and duration, viewable here.)
Why so hot?
While Europe has seen intermittent breaks from the heat this summer, the latter half of July saw a repeated southwesterly flow of warm, Saharan air push as far north as Scandinavia. Higher than normal pressure and unusually sunny skies boosted temperatures more than 20 degrees (F) above normal in many locations.
Considering average high temperatures in many European capitals peak between 74-80 degrees (F) during the warmest part of summer, the recent records are especially impressive.
After a wet spring, high soil moisture also helped raise humidity levels to uncomfortable levels. Relatively high dew points brought a number of “tropical nights,” a term many European weather agencies use to describe overnight low temperatures 20 C (68 F) or higher. Inadequate nighttime cooling has been a major source of discomfort, given limited use of air-conditioning across the continent.
For many European countries, the summer heat is the latest weather extreme of 2013, a year of unusual spring snowstorms, followed by record rainfall and severe flooding in early June. In late July, multiple tornadoes struck Italy, and severe thunderstorms pummeled through France.
Fortunately, the heat in central Europe is finally coming to an end this weekend. Earlier this week, a strong cold front triggered violent thunderstorms across Belgium (see video) and Germany, bringing hail and wind gusts up to 78 mph. The same cold front is edging eastward, and has knocked back temperatures some 10-20 degrees – closer to normal for the time of year.
With three weeks of meteorological summer remaining, a resurgence of heat looks unlikely. Yet as Germany and other European countries expect a long-term increase in the number of hot summer days, more heat records are likely to fall in the coming decades.