Being born and raised in North America, I know best the four seasonal cycle of life, though I know it is different in many other countries and continents. With the shifting global weather change, here in the Northeast it seems like it's changing to primarily a tri-seasonal model... and perhaps down from there.
In literature the seasonal cycle is one way of structuring stories - those that deal with the challenges and gifts of youth, adulthood, middle age, and the end of life. Some tales deal with multiple seasonal storylines, and others with the entire cyle. Once again, Joseph Campbell's mythological work deals extensively with this format, as do many other literary analysts. For more information, you can start with The Joseph Campbell Foundation website, which links to many of his lectures and works: http://www.jcf.org/new/index.php