What constitutes a month?
A breakdown of how long a month takes depends on the outcome of each game you play. If you win the game it goes faster and if you lose the game it goes slower and it is described in the rules.

If you look at the game calendar (page 16) at the end of the rules you will notice that it has 12 months each broken down into early and late. This shows that is possible to get 24 plays out of this legacy game. 

This is further broken down by the game end rules (Page 14) of which I am only including the part about game month

Game Win:


  You start your next game at the beginning of the next month


Game Loss:


  If this is the first time the month has been played, you must try the month again. If not, move on to the next month for your next game.


What this means is the better you play the faster the game will progress. This will get you between 12 games (If you win every time) and 24 games (if you lose the first attempt every month).

To sum it up just think that months are an indicator of how many more play sessions there might be left in the game.