In late June and late July 2019 there were two temporally distinct European heat waves, which set all-time high temperature records in Belgium, France, Germany, Luxembourg, the Netherlands, and the United Kingdom.
The first heat wave, in late June, killed over 567 people, and according to meteorologists it was caused by high pressure and winds from the Sahara Desert affecting large parts of the continent. It resulted in record-breaking temperatures for the month of June at many locations. France experienced temperatures in excess of 45 °C (113 °F) for the first time in recorded history. A national all-time record high temperature of 46.0 °C (114.8 °F) occurred on 28 June in Vérargues.
In late July, a second heat wave occurred, during which all-time records were broken by 3 °C (5.4 °F) in Belgium, by 2.1 °C (3.8 °F) in Germany and the Netherlands, by 0.3 °C (0.5 °F) in Luxembourg, and by 0.2 °C (0.4 °F) in the United Kingdom. The deaths of 868 people in France and one person in Belgium were reported, along with thousands of animals when ventilation systems in barns were overwhelmed. Due to high river water temperatures and sluggish flows, particularly in France and to some extent Germany, a number of thermal power stations that use once-through cooling and do not have cooling towers had to reduce output or shut down to avoid breaching environmental limits on river water temperature designed to protect aquatic life.
The above-normal hot condition in June is caused by an anomalous long-lasting anticyclone in the upper troposphere, which advects warm air from the Sahel and Mediterranean region and enhances incoming solar radiation and surface turbulent fluxes. The anomalous anticyclone results from an unusually-intensified British-Baikal Corridor pattern and a synoptic Rossby wave breaking event over Europe.
The July heat wave was caused by a strong omega block, consisting of hot, dry air from North Africa, trapped between cold storm systems. The high-pressure area of hot air, called Yvonne, stretched from the central Mediterranean to Scandinavia and was pinned between two low-pressure areas, one over western Russia and the other over the eastern Atlantic.
Total excess deaths are estimated to be around 2,500 during the summer months in 2019. Most of these were indirectly caused and were observed in statistical modeling later that year. Based on individual country counts, that figure may be an under estimate. The Dutch government reported 400 excess deaths in the week of the June heat wave, a figure comparable to those recorded during the 2006 European heat wave.
France estimated 1,435 additional deaths due to the heatwave. Public Health England reported 900 excess deaths from the heatwave. The Robert Koch institute reported 500 excess deaths in Berlin alone.
Belgium reported at least 716 excess deaths during the summer.
In June heat records were broken, on 30 June the temperature reached 38.5 °C (101.3 °F) in Innsbruck. This was a heat record for June in Austria, and also the highest temperature measured during the heatwaves.
Belgium recorded three consecutive days exceeding 30 °C (86 °F); 25 June was the hottest day during this period, with many places exceeding 32 °C (90 °F) and other places nearly reaching 35 °C (95 °F).
During the period of hot weather, environmental officials warned of poor air quality levels, which would especially affect the young, elderly and people with respiratory illnesses. It also affects small countries that rely on tourism as their main source of income.
On 24 July, the highest ever recorded temperature in Belgium was measured, reaching 40.2 °C (104.4 °F) in the town of Angleur, exceeding the previous record of 38.8 °C (101.8 °F), reached in 1947. On the same day, passengers were evacuated from a Eurostar train that had broken down between Halle and Tubize, as many began to fall ill due to the extreme temperatures. On 25 July, the national record was broken again, reaching 41.8 °C (107.2 °F) in Begijnendijk (Flemish Brabant). One death was reported.
The official KMI weather station in Uccle reported a maximum temperature of 39.7 °C (103.5 °F), while many other weather stations, some even close to the North Sea, reported temperatures in excess of 40.0 °C (104.0 °F).
The temperature record for June was recorded in Doksany and was 38.9 °C (102.0 °F). High temperatures also complicated rail transport in the Czech Republic.
On 22 July 2019 the DMI issued a warning for high temperatures possibly up to 35 °C (95 °F). On 24 July, the temperature reached 30.9 °C (87.6 °F) in Åbenrå, Svendborg and Nykøbing Falster.
On 25 July the temperature reached 32.0 °C (89.6 °F) in Vordingborg & Holbæk. Temperatures for that day were forecasted up to 35 °C (95 °F), but due to afternoon thunderstorms the temperature only reached a maximum of 32.0 °C (89.6 °F).
On 28 July, Helsinki recorded a temperature of 33.2 °C (91.8 °F), breaking the city's previous record. On the same day, 33.7 °C (92.7 °F) was recorded in Porvoo.
France was one of the most affected countries from the heatwave, with much of the country exceeding 32 °C (90 °F) on 26 June. Météo France issued an Orange Alert for much of the country due to exceptionally hot temperatures, excluding coastal regions, e.g. Brittany and the northern part of Hauts-de-France. Four departments of France were put on Red Alert: Bouches-du-Rhône, Gard, Hérault and Vaucluse. Owing to building codes with old structures common across the country, numerous buildings in France lack air conditioning.