January 2028 has 31 days. The 1st falls on a Saturday and the 31st on a Monday, so the grid runs to 6 rows.
Federal holidays this month: New Year's Day on January 1 (a Saturday), and Martin Luther King Jr. Day on January 17 (a Monday).
Each day cell carries two writing rules beneath the date, which is enough for an appointment and a reminder without the cell becoming cramped.
The week runs Sunday to Saturday, the usual US arrangement.