The impacts of extreme weather events on lakes have received increasing attention in recent years. This is because the severity and frequency of such events have increased and are predicted to increase even further in the years to come due to ongoing climate change. Furthermore, advances in real-time high-resolution monitoring now make it possible to track even the short-term effects of such events. Episodic events may potentially have strong effects on lake ecosystems in the short-term and, if severe, also on the longer term. A Special Issue of the journal Water is being edited by PROGNOS team members Erik Jeppesen, Don Pierson and Eleanor Jennings on Effect of Extreme Climate Events on Lake Ecosystems. The special Issue welcomes contributions on the effects of extreme weather events on lake ecosystems, such as change in precipitation leading, for example, to changes in nutrient and dissolved organic carbon (DOC) loading and salinity, or how heatwaves and changes in the intensity and frequency of winds affect both stratification and the biological community and processes. We also welcome contributions on how hurricanes may lead to immediate and long-lasting changes in lake ecosystems, as well as papers dealing with resistance and resilience to extreme events or showing sudden regime shifts.