Depends where you are in the world. The US, or at least the major networks there, tends not to stray too far from the 10-13 or 23-26 episodes is a "season" (UK English will tend to use series for season* and series for whole show too) and is usually broadcast between September and some time around Easter depending upon how many weeks break you had for all the US holidays. UK "seasons" might well be only 6 episodes and can happen anything from a few weeks apart to a few years (
https://en.wikipedia.org/wiki/List_of_Last_of_the_Summer_Wine_episodes ), perhaps longer still and that is before you consider Christmas specials. Go online and what gets called a season has even less meaning.
*"did you see series 2?" and "I saw this new series last night, it was awesome" both being phrases you might hear.