In an organized sports league, a typical season is the portion of one year in which regulated games of the sport are in session: for example, in Major League Baseball the season lasts approximately from the last week of March to the last week of September. In other team sports, like association football or basketball, it is generally from August or September to May although in some countries - such as Northern Europe or East Asia - the season starts in the spring and finishes in autumn, mainly due to weather conditions encountered during the winter.

A year can often be broken up into several distinct sections (sometimes themselves called seasons). These are: a preseason, a series of exhibition games played for training purposes; a regular season, the main period of the league's competition; the postseason, a playoff tournament played against the league's top teams to determine the league's champion; and the offseason, the time when there is no official competition.