River levels ebb and flow throughout the year. In Europe, the snow melting off the mountains in the spring can lead to high water levels, making it difficult for larger ships to pass under low bridges. On the flip side, the heat of the summer months can lower water levels, rendering stretches too shallow for cruise ships.
But that doesn’t mean that there is never low water in the spring or high water in the summer. A mild winter with little snowfall or a particularly stormy summer can throw everything out of whack. Case in point: While June 2016 saw low water levels on the Elbe, the Danube’s waters were higher than normal. There are also waterways that have become almost impossible to consistently cruise in any season, including Italy’s Po River.
River cruises in Asia and South America are not as dependent on water levels as those in Europe. The smaller ships can navigate shallower waters, and the lack of development (without those pesky bridges) means ship height is not a major issue. In contrast, high water means the ability to travel deeper into certain areas, while low water can increase your chances of spotting wildlife.Amazon River cruises operate year-round, through the high waters from December to May and low waters from June to November. Cruises along Asian rivers like the Mekong and the Irrawaddy are typically suspended between May and July, when the temperatures are high and the waters are low.