Scorching Heatwave Followed by Summer's Violent Outburst - Heat arrives first, followed by the summer tempest
In the heart of summer 2025, Bavaria, Germany, is bracing for a significant heat wave, with temperatures forecasted to reach up to 39 degrees. The German Weather Service (DWD) has announced these high summer temperatures for the first week, with the second week expected to start sunny and warm, with temperatures ranging from 32 to 39 degrees.
However, these hot conditions are not the only concern. There is an increasing risk of thunderstorms, particularly at the Alpine foothills and the Bavarian Forest, during the second week. Thunderclouds are approaching Bavaria, and isolated showers or thunderstorms are possible on Saturday night.
The combination of swimming weather and school holidays is expected to attract many people to the lakes in Bavaria. Yet, the safety measures during such high temperatures and thunderstorms are of utmost importance.
When it comes to heat safety, staying hydrated, avoiding strenuous outdoor activities during peak heat hours, seeking shade or air-conditioned places, and using cooling methods like water sprays are crucial. As for storm safety, it is essential to monitor weather alerts from the DWD, avoid open water and lakes during thunderstorms to prevent lightning risks, and secure outdoor belongings against strong winds or hail.
Water safety is another concern, with bathing during or immediately after storms carrying increased risks from rough water conditions and possible lightning strikes. Authorities often issue warnings during such compound weather events. The Water Rescue Service and the German Lifesaving Association (DLRG) have advised against jumping into water overheated, and to cool down gradually before swimming. They also recommend not swimming alone, or to use a swimming buoy on lakes, and above all not to underestimate one's own strength.
The heat wave follows a period of rain but also an overall dry spring, leading to critical wildfire risk in parts of Germany. This can indirectly affect air and water quality locally near Bavaria. Maintaining awareness of combined hazards—heat, storms, wildfires—and adapting safety measures accordingly is crucial.
Unfortunately, the increased risk of blue-green algae at Franconian lakes has led to no bathing bans yet, but a warning about blue-green algae has been issued for all bathing areas at the Altmühlsee in Bavaria. Contact with blooming blue-green algae can have unpleasant consequences such as nausea, fever, or even shortness of breath.
In some alpine valleys, temperatures may drop to 12 degrees on Wednesday night, providing a mild contrast to the daytime heat. The night to Friday is expected to be mild, with showers not ruled out.
When paddling or on stand-up paddleboards, life jackets should be worn for safety. The safety advice for swimming and paddling in Bavaria emphasizes the importance of wearing life jackets for safety while paddling or on stand-up paddleboards.
As Bavaria navigates this challenging weather period, it is crucial for residents and visitors to stay informed, stay safe, and enjoy the summer responsibly.
The Commission has also been informed about the progress made in implementing the safety programme, considering the severe weather conditions, including the approaching thunderstorms and high temperatures forecasted in Bavaria.
Despite the cooler temperatures expected on Wednesday night, it is essential to maintain awareness of the combined hazards, such as heat, storms, and wildfires, while enjoying the summer weather responsibly.