MLS is the top-flight professional soccer league for the US and Canada that typically begins by the end of Winter. However, it is just the regular season phase of MLS played across the Eastern and Western conferences that begins in February, running until October.
The CONCACAF Champions Cup also starts in February and runs through June, where teams' participate based on their positions in MLS, apart from cup competitions including the US Open Cup of the previous season.
Between mid-July and mid-August, when the Leagues Cup tournament - comprising of all MLS and Liga MX teams - is held, MLS takes a break. This is also when the MLS All-Stars team take on a selected international side or selected players from another league in an one-off annual encounter.
The second part of MLS or the playoffs begins its matches in October and winds up by December, leading to the MLS Cup tie.
So in all, MLS is held over the length of around nine months.