In focus | July 2024

Rainiest year on record – but with great regional variation


On average, more precipitation than usual fell over Germany in the last 12 months. However, the regional differences are large.

The period from July 2023 to June 2024 was the wettest 12-month period since records began in 1881 (DWD 2024). The area average of the annual precipitation was analysed for this purpose. However, there were major regional and temporal differences. Particularly noteworthy are the extreme precipitation events that led to widespread flooding, especially in Lower Saxony, Bavaria, Baden-Württemberg and Saarland. These are also reflected in the annual totals in Fig. 1.

Figure: Absolute precipitation anomaly in the period from July 2023 to June 2024 [mm/a]. Comparison is made with the long-term average 1991-2020. Analysis: F. Boeing (UFZ Drought Monitor).
Fig. 1: Absolute precipitation anomaly in the period from July 2023 to June 2024 [mm/a]. Comparison is made with the long-term average 1991-2020. The value "600" therefore means that it rained 600 litres per square metre more than expected over the long term.
Data source: DWD-CDC station data (2024). Analysis: F. Boeing (UFZ Drought Monitor).

If we look at the spatial distribution of precipitation across Germany and compare it with the average precipitation over the last 30 years, it becomes clear that significantly more precipitation has fallen on average in the west of Germany, in the Lüneburg Heath and the Altmark. However, the further east you look, the more the picture changes. In the Uckermark, in the Ore Mountains and in the Swabian-Franconian stepped landscape, only as much precipitation fell as the annual average over the last 30 years. The precipitation deficit of the past (dry) years has therefore not been reduced uniformly across Germany as a whole and in some regions not at all.

The picture becomes even more differentiated with regard to the deviations of the respective monthly averages of the last 12 months: none of the last 12 months shows a uniform picture of deviation from the long-term average across Germany as a whole (Fig. 2).

 

Figure: Relative deviation of monthly precipitation in the period from July-December 2023 (top) and January-June 2024 (bottom). Evaluation: F. Boeing (UFZ Drought Monitor)
Fig. 2: Relative deviation of monthly precipitation in the period from July-December 2023 (top) and January-June 2024 (bottom) [%] - compared with the long-term average of the respective month from 1991-2020.
Data source: DWD-CDC station data (2024). Evaluation: F. Boeing (UFZ Drought Monitor)

Precipitation and its deviations are important factors for the severity and dissolving of drought events. Only in 2018 and 2019, drought and heat led to damage totalling around 35 billion euros in Germany.

In July 2023, the initial situation of soil moisture down to a depth of two metres in Germany was characterised by drought (Fig. 3). The above-average precipitation resolved the drought in large parts of Germany. However, it is also evident that some regions are still too dry. This is particularly the case in south-east Germany.

 

Figure: Soil moisture drought in the total soil down to a depth of two metres in July 2023 (left) and June 2024 (right). Source: UFZ Drought Monitor
Fig. 3: Soil moisture drought in the total soil down to a depth of two metres in July 2023 (left) and June 2024 (right). Source: UFZ Drought Monitor

Sources:

DWD (2024): https://www.dwd.de/DE/presse/pressemitteilungen/DE/2024/20240703_die-zwoelf-nassesten-monaten-seit-messbegin_news.html?nn=16210

DWD-CDC (2024): https://opendata.dwd.de/climate_environment/CDC/

UFZ Drought Monitor: https://www.ufz.de/duerremonitor