With an average temperature of 2.2 degrees Celsius, the winter of 2024/2025 was 0.5 degrees warmer in the Ruhr catchment area than in the same period in 1991/2020, according to the Ruhrverband's analyses. It was therefore the twelfth excessively warm winter that the Ruhr catchment area has experienced in succession. Every single month this winter was also warmer than the respective comparison period: December 2024 by 1.1 degrees, January and February 2025 by 0.3 degrees each. As a reminder, the previous winter of 2023/2024 was actually the second warmest since records began, and February set a new record with 4.8 degrees above the long-term average.
After three wet winters in a row (2021/22 plus 20 %, 2022/23 plus 13 % and 2023/24 even plus 53 %), this winter was too dry at minus 12 % compared to the average for the years 1927 to 2024. February 2025 was particularly noticeable here, which was 74 % drier than the comparative period.
Nevertheless, the watercourses in the Ruhre catchment area had a sufficiently high water supply throughout the winter. No subsidy from the reservoirs was required to maintain the statutory minimum discharge, although a low water phase set in from mid-February due to the lack of precipitation. At the start of winter on 1 December 2024, the total fill level of all dams was 81.1 %. The further development of the reservoir content was characterised by repeated flood-related damming and retention phases, which were followed by damming and spillway phases to restore the prescribed flood protection areas. Since mid-February, the reservoir level has risen only slightly, so that on 28 February the reservoirs were 87.2% full, which is almost average for the time of year. The dam system is therefore well prepared for both dry periods and foreseeable seasonal flood events.