As of 2015, US Youth soccer is held in most states between September through November and February through May. Major league soccer holds games from March 6th through October 25th with their playoffs occurring after the regular season and extending into December.
Youth soccer does not hold to any traditional season for soccer. Every state implements their programs differently, and as a result, they start the season and end it at various times during the fall and spring months. The more competitive leagues within youth soccer may also contain shorter breaks during the months they are playing.
Major League Soccer generally runs for most of the year with only a short break in late winter. Their season is longer because it contains 20 different clubs with each team playing a total of 34 times in the regular season. The 12 best teams during the regular season continue to play in the playoffs well into November and December.