What time period were the Axis powers most successful in World War 2?

The Axis powers were most successful in World War II during the early years of the conflict, specifically from 1939 to 1942. This period saw rapid expansions, including Germany’s swift victories in Poland, France, and the low countries, as well as Japan's advances in Southeast Asia and the Pacific. However, their momentum began to wane after significant defeats, such as the Battle of Stalingrad in 1942 and the Battle of Midway in the same year, which marked the turning point in the war.