2019 Precipitation anomalies; Credit: AgriMeteo

At the end of 2019, the State Weather Service of Luxembourg's Ministry of Agriculture, Viticulture and Rural Development (Administration des services techniques de l’agriculture - ASTA) published its regional weather analysis and consequences for agriculture and viticulture.

Overall, the meteorological situation for 2019 proved to be too warm and too dry in the north of the Grand Duchy, leading to a difficult year for agriculture and viticulture.

Particularly noteworthy are national temperatures (+ 0.9°C in Ösling and + 1.0°C in the south), a record temperature recorded in Steinsel (40.8°C in July) and another in Remich (23.9°C in February), a tornado and local rain deficits (up to -136 mm in Arsdorf). Depending on the situation, viticulture and fruit growing suffered considerable losses. In agriculture, forage production in meadows and pastures as well as maize cultivation suffered from the drought.
 
The weather data come from the measurement network of 32 automatic weather stations from across Luxembourg. This year the values ​​of the four representative stations Asselborn (north), Clemency (south-west), Remich (Moselle valley) and Grevenmacher (Moselle valley) were compared with the average values ​​for the reference period 1981-2010.

The mean temperatures at these four stations were above the values ​​of the reference period, with the smallest deviation in Asselborn and Remich (+ 0.8°C) and the highest deviation in Clemency with + 1.0°C. In Luxembourg City, where temperatures have been measured since 1838, 2019 was the 26th warmest year with a deviation of + 0.2°C. Monthly averages under the reference period were recorded only in January, May and November. May in particular was relatively cool across the country, with an anomaly of up to -2.3°C in Asselborn. After the high temperatures in the previous months, this cold spell led to severe frost damage and loss of yield, especially in wine growing and also in fruit growing. The highest positive monthly deviation was measured in Asselborn in February at + 3.5°C. But June was also much warmer than the reference period with an anomaly of + 2.7°C in Asselborn.

Temperature records: The extremely high temperatures of July 25 should also be emphasised, at which daily maximum values ​​above 35°C were measured in all 32 ASTA stations and the 40°C mark was exceeded at 4 stations. The absolute maximum was measured in Steinsel at 40.8°C, which is a new record since weather records started in 1838. But also on 27 February, a new record for a temperature peak in February was measured at 23.9°C at the Remich station. Here the previous record on 24 February 1990 was recorded at 17.9°C. The high temperatures repeatedly led to unstable air masses in the summer, in which local thunderstorms developed. This led to hailstorms on 19 June in the northwest of the country; and on 9 August a category F2 tornado developed in the southwest of the country, which caused major damage, particularly in Petange and Bascharage.

The rainfall in 2019 divided the country in two. While here was a rainfall deficit in the north, in the south of the country there was an excess of rainfall compared to the long-term average. The largest deficit was recorded in Arsdorf with −136 mm, while in Koerich there was a surplus of +62 mm. In Asselborn, the precipitation amounts were below the values ​​of the reference periods during all months except June and October. January, in particular, was dry with a deficit of −44 mm, and the precipitation amounts could not make up for this deficit for the rest of the year. In Remich, on the other hand, there was an above-average amount of rain from March to May, as well as in October and November, which meant that the annual precipitation sums were close to the long-term averages and the annual sum registered a surplus of +60 mm. Agriculture, wine and fruit growing suffered from late frosts, temperature records and drought. In 2019, wine and fruit growing suffered heavily regionally from the late frost of early May in 2019, which led to considerable yield losses, depending on the situation. In viticulture and fruit growing, strong sunshine also caused sunburn.

Even if the amounts of precipitation, especially in the south of the country, are above the long-term values ​​over the year, the very high temperatures, especially in the summer months, led to high evapotranspiration values, which dried soil to a great extent, so that agriculture suffered from drought and yields varied depending on the location and type of culture. The onset of precipitation in October somewhat replenished the reserves in the upper strata, but is not yet sufficient to compensate for the water deficit of the past two years in the deeper strata. For agriculture in particular, it would therefore be necessary that the water reserves in the soil could be continuously filled over the winter in order to fully compensate for the lack of water. Forage production in the meadows and pastures in particular, as well as maize cultivation, suffered greatly from the rainfall deficits both in 2019 and in previous years.
 
All recorded data from the 32 ASTA weather stations can be accessed on www.agrimeteo.lu.