calendar-month-header is a variable defined in `calendar.el'.
Its value is

(propertize (format "%s %d" (calendar-month-name month) year) 'font-lock-face 'calendar-month-header)

  • This variable may be risky if used as a file-local variable.

Expression to evaluate to return the calendar month headings.
When this expression is evaluated, the variables MONTH and YEAR are
integers appropriate to the relevant month. The result is padded
to the width of `calendar-month-digit-width'.

For examples of three common styles, see `calendar-american-month-header',
`calendar-european-month-header', and `calendar-iso-month-header'.

Changing this variable without using customize has no effect on
pre-existing calendar windows.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.3 of Emacs.