January 2030 has 31 days. The 1st falls on a Tuesday and the 31st on a Thursday, so the grid runs to 5 rows.
Federal holidays this month: New Year's Day on January 1 (a Tuesday), and Martin Luther King Jr. Day on January 21 (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.