Slovenia's heat and Europe's record heat

Europe faced one of its most extreme heatwaves this summer, with record-breaking temperatures shattering historical benchmarks across multiple countries. On June 22, the thermometer in Andújar, a town in southern Spain, registered 45.1 degrees Celsius, marking one of the highest readings recorded in Europe. Just nine days later, on June 31, the weather station in Möckern Drewitz, Saxony-Anhalt, Germany, measured 41.8 degrees Celsius, surpassing the previous German national record of 41.2 degrees set in 2019. Meanwhile, in Slovenia, Ljubljana experienced eight consecutive days with daily high temperatures exceeding 35 degrees Celsius by August 5, the longest streak since systematic measurements began by the Slovenian Environment Agency (ARSO). These developments have left meteorologists stunned, as such conditions were not anticipated even under the most pessimistic climate scenarios. The heatwave has been widespread, affecting numerous European nations including Slovenia, Germany, Switzerland, Austria, the Czech Republic, Slovakia, Poland, Croatia, Hungary, Ukraine, Belarus, Romania, and Serbia. Across these regions, temperatures frequently exceeded 40 degrees Celsius, with some areas recording unprecedented highs. In early August, thousands of temperature records were broken across the continent, with many stations reporting all-time highs. The phenomenon was so severe that the World Meteorological Organization (WMO) and the Copernicus Climate Change Service declared June 2026 the hottest June ever recorded for western Europe and the second-hottest for the entire European continent. The average temperature over the European landmass reached 19.14 degrees Celsius, which is 1.78 degrees above the 1991–2020 reference period. Western Europe saw an even more dramatic increase, averaging 20.74 degrees Celsius, a deviation of 3.06 degrees from the norm. According to data compiled by the American analytical portal Yale Climate Connections, based on assessments by renowned international observer of temperature extremes Maximilian Herrera, the June heatwave alone broke ten absolute national records in the European Union and established 420 new records at stations with at least four decades of measurement history. Every European country except Italy and Greece set new records for the highest minimum nighttime temperatures. A selection of record values in European cities during the summer of 2026 illustrates the severity of the situation. The physical driver behind these extreme temperatures was a persistent dome of high atmospheric pressure in the upper troposphere, known to meteorologists as a heat dome. This dome functions as a lid under which air compresses and warms due to solar heating, while dry southerly winds from the Sahara further elevate temperatures in lower layers of the atmosphere. The system became linked to what meteorologists call an omega block, named after the Greek letter omega, which the high-pressure ridge outlines in the flow pattern of the jet stream. This blocking pattern kept the weather system stationary for up to ten days. The heat dome formed three times between the end of June and the first week of August, each time over different parts of the continent. The first episode affected western and central Europe, stretching from Portugal to Poland. The second expanded over the Iberian Peninsula and southern France, where temperatures remained in the low to mid-40s throughout much of July. As the heatwave continued into August, concerns grew over the potential for further extreme weather events, particularly with the El Niño phenomenon expected to intensify global temperatures during the months of August through October. With record-low water levels observed in the Danube River and additional heatwaves forecasted, the impact of these climatic extremes continues to unfold across Europe.