Each column is labeled when a month begins inside it: the month changes between its Monday and Sunday, or its Monday is the 1st; the label names the Sunday's month. Months that began before the window stay unlabeled.
Each column is labeled when a month begins inside it: the month changes between its Monday and Sunday, or its Monday is the 1st; the label names the Sunday's month. Months that began before the window stay unlabeled.