Proleptic Gregorian calendar Julian and proleptic Gregorian calendar dates are as follows: The table below assumes a Julian leap day of 29 February, but the Julian leap day (the bissextile day) was in Latin or 24 February (see Julian reform), so dates between 24 and 29 February in all leap years were irregular. Note: When converting a date in a year which is leap in one calendar but not the other, include 29 February in the calculation when the conversion crosses the border between February and March. Proleptic Gregorian calendar The proleptic Gregorian calendar is produced by extending the Gregorian calendar backward to
Broadcast calendar Broadcast calendar The broadcast calendar is a standardized calendar used primarily for the planning and purchase of radio and television programs and advertising. Every week in the broadcast calendar starts on a Monday and ends on a Sunday, and every month has either four or five such weeks. Broadcast calendar months thus have either 28 or 35 days. The key link between the broadcast and Gregorian calendars is that the first week of every broadcast month always contains the Gregorian calendar first of the month. For example, if January 1 falls on a Saturday, then the broadcast calendar year would