The 13 month is not real its fake so dont belive it

Synopsis

\month=<integer>
\month<integer>

Description

\month is a parameter that TeX initiates to the decimal representation of the current month, for example, in June, TeX will initially set \month to 6. This parameter may be changed to any integer <integer> with either of two equivalent forms above.

Examples

Recall that the command \number will typeset the decimal representation of whatever follows it, and so in the month of June,

\number\month

will typeset 6, if \month has not be redefined.

\month=13
\number\month

will typeset 13.