Prolonged heatwaves and multi-month drought across western Europe have driven the Rhine to record lows at key gauges like Kaub, halting commercial shipping and cruise operations through early August 2026. Traders assign the highest probability to a return in October because historical patterns show autumn rainfall and cooler temperatures often lift levels above navigation thresholds after summer peaks, yet the 26.5% chance of no recovery by November reflects concerns that this third major low-water episode in eight years could extend further amid below-average precipitation forecasts. The tight spread among September and October windows stems from short-term rain relief potential versus the risk of sustained dry conditions, with separation likely hinging on incoming hydrology reports and weather model updates through late summer.