Some of the short-term effects of World War II are the end of imperial aggression, the end of the Great Depression in the United States, and the division of Germany into four parts.
Italy and Germany surrendered to the allied powers (US, UK, France, and Russia, among others) in 1944. With this, the allied powers focused their attention on Japan. On August 6, 1945, the US dropped the atomic bomb on Hiroshima. Two days later, Russia declared war on Japan. The next day, August 9, 1945, the US dropped a second atomic bomb on Nagasaki. Five days later, Japan unconditionally surrendered to the allied powers. This marked the end of WWII and the end of imperial aggression and territorial expansion; Germany, Italy, and Japan all attempted to grow their empires/nation-states by invading and taking over neighboring lands. One short term impact of WWII was to stop this.
Another short-term effect was the end of the Great Depression in the United States. While other allied powers experienced a short period of inflation as a result of the costly war, the growth of manufacturing industries in the United States led to an economic boom. Shortly after WWII, a growing mass consumer culture erupted in the United States and families were able to move to the suburbs and afford more than they were before.
Another short-term effect of WWII was the division of Germany. Eastern Germany was controlled by the Soviet Union. Western Germany was divided up between the US, UK, and France. Western Germany was slowly transferred back into German control, but Eastern Germany remained part of the Soviet Union for much longer. The city of Berlin, inside East Germany, was also split into parts and controlled by both Germany and the Soviet Union until the fall of the Berlin Wall in the late twentieth century.