Asia is a vast continent full of popular big cities and there is no wrong time to visit. The most popular region, the southeast, is where the most popular destinations are. The summer is the most popular time to visit Thailand & Vietnam, however, it's also the hottest time. You can try your luck at the Japanese cherry blossoms during the spring or fall foliage colors in Seoul during the fall. Asia has something for everyone and any time you are able to visit is the best time, especially on a
guided Asia tour.