Record temperatures for summer 2019; Credit: ASTA

According to the latest ASTA weather bulletin, Summer 2019 in Luxembourg was characterised by three heatwaves, record high temperatures, a rain deficit and a tornado.

The State Meteorological Service of the ASTA (Department of Agricultural Services - Ministry of Agriculture, Viticulture and Rural Development) has carried out a weather analysis for summer 2019, taking into account the period from 1 June to 31 August 2019. The analysis looked at the network of 32 automatic weather stations across the Grand Duchy.

Once again, this year's weather data was compared with the averages of the reference period 1981-2010. A special focus was placed on the following four representative stations: Asselborn (north), Clemency (south-west), Remich (Moselle) and Grevenmacher (Moselle). The mean temperatures for each of these regions exceeded the long-term averages. 

More specifically, temperatures were up 1.6°C along the Moselle and the south of the country and 1.3°C in the north (Oesling). June was particularly warm with an increase of 2.7°C recorded in Asselborn and a first heatwave bringing extreme heat to the Grand Duchy towards the end of the month. 

Whilst July initially saw temperatures rise the least (+0.4°C in Asselborn), a second heatwave was recorded from 25 July with maximum daily temperatures exceeding 35°C at all ASTA stations. In addition, four stations recorded temperatures exceeding 40°C; indeed, Steinsel recorded a new record high temperature (since weather records began in 1838) of 40.8°C during this period.

The first three weeks of August were relatively close to the long-term average but the summer ended with a third heatwave, albeit not as pronounced as those in June and July. Nevertheless, high temperatures leading to unstable air masses caused thunderstorms in Luxembourg, particularly in the north-west of the country on 19 June and in the south-west on 9 August, when an F2-rated tornado (wind speeds between 113 to 157 MPH) caused significant damage in Pétange and Bascharage.

Summer 2019 also brought rainfall deficits, particularly in the centre of the country, with a decrease of up to 102mm recorded in Arsdorf. July saw strong deficits in Asselborn and Clemency (-32mm), as well. Meanwhile, the two Moselle stations saw a deficit across all the summer months, with Remich recording a mere 17mm of precipitation in July.