The Minnesota Legislature meets each year, functioning on a two-year cycle called a biennium. The first year of the biennium is called the "long year," and lasts from January to mid-May. The second year is called the "short year," and typically runs from February through the end of April.
Since 1973, the Minnesota Legislature has met in session every year, the result of a 1972 constitutional amendment, which allowed for "flexible sessions." The 1972 amendment did not require annual sessions of the Legislature. Rather, it just allowed for them to happen.
When the Minnesota Constitution was written in 1857, it placed no limit on the number of days the Legislature could meet in session and did not prohibit the Legislature from meeting each year. Three years later, sessions were limited to 60 days in length. Until 1877, the Legislature met each year. It was in 1877 that the Minnesota Constitution was amended to provide for biennial sessions with a limit of 60 days. In 1888, the number of days was increased to 90, and in 1962, increased again to the current 120 days.
From 1877 until 1973, when lawmakers redefined the term, legislative days were measured consecutively, meaning that the clock began ticking the moment the Legislature convened, excluding Sundays. Exactly 120 calendar days (plus Sundays) after convening, the Legislature had to adjourn. Following the passage of the 1972 amendment, lawmakers in 1973 redefined a legislative day as only those days when either the House or Senate met in full session. Days on which only committees meet are not considered official legislative days. This definition of "day" left the 120-day constitutional maximum untouched, but allowed lawmakers to spread the days over a two-year period. This 'flexible' system is unique in the United States.
For historical information on Minnesota legislative sessions, see Sessions of the Minnesota State Legislature and the Minnesota Territorial Legislature and Special Sessions of the Minnesota Legislature and the Minnesota Territorial Legislature.