Summer sunsets in the northern region grow eerily dark in July.
In July 2025, the German region of Schleswig-Holstein experienced heavy rainfall, largely associated with low-pressure systems named Isaac and Karlheinz. These systems contributed to unstable weather characterized by thunderstorms, heavy rain, and flooding risks in the region during the first half of the month.
Early July saw an unstable trough situation with thunderstorms and areas of heavy rain, raising the risk of flooding over Schleswig-Holstein and Hamburg. Around July 29-30, heavy rain was reported, impacting events such as Wacken Open Air, with police warnings about expected heavy precipitation overnight and into early morning. Local reports confirm intense rain falls with nearly an inch occurring within a few hours, causing flooding issues in urban and rural areas.
The German Weather Service (DWD) made initial evaluations from its approximately 2,000 measuring stations. However, the detailed synoptic characteristics of Isaac and Karlheinz, such as exact tracks, pressure values, or formation mechanisms, are not explicitly described in the available information.
For typical July conditions, Lübeck in Schleswig-Holstein shows varying daily precipitation from light to moderate intensity. The heavy rainfall in July 2025 appears to be above average and influenced by these storm systems.
In contrast, July 2023 was a gloomy month for Schleswig-Holstein, with the sun making a rare appearance, shining for only 167 hours. The total rainfall in Schleswig-Holstein in July 2023 was 138 liters per square meter, exceeding the reference value by 72 percent. The average monthly temperature in Schleswig-Holstein in July 2023 was 18.3 degrees Celsius, 2.0 degrees above the long-term average (16.3 degrees Celsius).
The sunshine hours in Schleswig-Holstein in July 2023 are fewer than the long-term average. In the long-term average of the international reference period 1961 to 1990, the sun shone in Schleswig-Holstein for 210 hours in July. Schleswig-Holstein's sunshine hours in July 2023 tie with Lower Saxony for second-to-last place in the state comparison.
The DWD is responsible for weather evaluations and data collection in Germany. While the specifics of the low-pressure systems Isaac and Karlheinz remain to be fully explored, their impact on the weather in Schleswig-Holstein in July 2025 is clear. The heavy rain and associated flooding disrupted the region's weather, causing localized flooding mainly in the latter half of the month.
The meteorological disruptions in Schleswig-Holstein in July 2025, primarily in the latter half of the month, were largely attributed to the low-pressure systems Isaac and Karlheinz, influencing environmental-science studies on weather-forecasting. These systems led to heavy rain, flooding risks, and potential impact on events such as Wacken Open Air.
