European Heatwave and Drought

20 March 2019

DANIEL KNÖS – Senior Analyst, JLT Re, Stockholm, Sweden

The spring of 2018 brought unusually high temperatures into Europe. The year started out fairly cold with February and March being colder than the average during the last decades. However as spring arrived the temperatures started to rise above normal and with the exception of the Iberian Peninsula, they have remained above average in all of Europe from April to October.

The temperature anomalies varied depending on region but ranged between one and three degrees above average with the highest deviations being in the Alps region, France, Germany, Poland and Southern Scandinavia. In Europe, summer temperatures exceeded the average by 2.1 degrees. July was particularly hot, especially in Scandinavia where the average temperatures were comparable to those typical of Central and Southern Europe. Both Norway and Finland had their warmest July months on record and in many areas across the Nordics the temperatures in July were more than 4 degrees above average. A number of weather stations in Scandinavia had the highest average summer temperatures ever recorded, with observation records ranging over 250 years. Extreme temperatures were also observed in Southern Europe, with Paris experiencing its second highest temperature ever recorded since 1873 of 39.7 degrees Celsius, only beaten by the 40.4 degrees Celsius from 1947. 

Figure 1: Temperature anomaly in Europe from June to August 2018. (Source: Deutscher Wetterdienst, DWD)

European Heatwave

Figure 2: Precipitation in Europe from June to August 2018 as percentage of average 1981-2010. (Source: Deutscher Wetterdienst,

European Heatwave

In combination with the high temperatures, Northern Europe also experienced less rainfall than usual during the summer months, leading to overly dry conditions. The first half of the summer was the driest on record in the UK, and during all the summer months, Sweden, Benelux and most parts of Germany received about half as much rain as during an average summer.

One of the reasons for these high temperatures was the location of the polar jet stream. The jet stream is formed of westerly winds travelling around 10 kilometers above the earth’s surface, between latitudes 30 to 60 degrees. It serves as a barrier between warm air in the south and the cool air in the north. This summer, the jet stream remained at an unusually northerly location, allowing for warm air from the south to heat up large areas of Northern Europe.


Forest fires

As a consequence of the warm and dry conditions in Northern Europe and Scandinavia in particular, the risk of wildfires was high. The conditions were particularly severe in Sweden, with the highest fire risk warning being issued in many areas. Fire-hazardous activities were prohibited as a result, from camp fires to activity from the forest industry. Despite the precautions approximately 80 fires of various sizes took place all around the country, covering a total of 23 thousand hectares and damaging a total of 2.1 million cubic meters of forest. With a few exceptions, most of the fires were small and locally contained. The largest individual fire, located in the middle of Sweden, covered a total area of 9 thousand hectares.

Figure 3: Smoke billows from a fire outside Ljusdal, Sweden on July 18, 2018. (Source: Maja Suslin/TT via © 2018 The Associated Press)

European Heatwave

Southern Europe additionally experienced wildfires, with far more severe consequences. In the coastal area of the Attica region in Southeast Greece, wildfires killed around 100 people by the end of July. The fire started in a forest area five kilometers inland from the Greek east coast, approximately 20 kilometers northeast of Athens. Due to the dry conditions and high wind speeds the consequences became severe. In many areas wind speeds exceeded 60 kilometers per hour, reaching numbers around 100-120 kilometers per hour locally. This caused the fire to spread rapidly, in many places around three to four kilometers per hour. In total, the fire covered an area of 1,300 hectares and due to lack of visibility and limited routes to the coastline, many people were trapped in the flames and the smoke.


The weather conditions also lead to difficulties for the agricultural sector in Europe. Low precipitation from late spring and through the summer reduced European wheat harvests by 9% from last year, with Northern Europe primarily affected. Swedish production of cereal grains was reduced by 50% compared to last year, and is the lowest number since 1959. In Germany and Poland, the harvests were down 18% and 14%, respectively and in the Baltic states, the corresponding numbers had a roughly 30% reduction. As a response to the dry conditions and feed shortages, meat production was up by 2% as farmers brought forth the slaughtering of animals.

Still a few months into the fall and early winter, the long-time drought conditions are having further consequences. The dry weather has brought unusually low water levels in rivers across Europe. The River Rhine in Germany, which is an important shipping route, had critically low water flow in some places through July and August. Although the late fall was an improvement, the water level remained low and traffic on the river was vastly reduced. This had an effect on both the cargo and tourism industries, and large ships had to travel with less cargo on board to limit the risk of going aground.

For the insurance market, the losses from the 2018 summer season are rather low, as losses are normally driven by other perils such as wind, flood and earthquake. As the frequency and severity of fire events and severe heat conditions rise, JLT Re experts will continue monitoring and reporting on such conditions both across Europe and globally.