When you type waituntil /?, you receive:

Version 1.12, Copyright (C)2002, Frank P. Westlake.
Waits until the specified time or for the specified number of milliseconds.

WaitUntil \[/B | /C\] /W | time | milliseconds

/B           Generate a CTRL-BREAK at the indicated time.
/C           Generate a CTRL-C at the indicated time.
/W           Wait until CTRL-C, CTRL-BREAK, logoff, or system shutdown.
time         An absolute time in the format \[y-m-d\] h:m\[:s\[.mss\]\].
             If any of y, m, or d are 0, the current value will be used for
             that period. If the date is not specified and the time is already
             past, tomorrow's date will be used.
milliseconds The desired number of milliseconds to wait.

When the time has expired this program will simply exit. If the /B or /C
switches are specified a CTRL-BREAK or CTRL-C event will be sent to the console
group before exiting.

If /W is specified the program will continue to run until interrupted. The exit
code will identify the type of interruption.

  :: To perform a task on the 5th of this month at 08:00:
  WaitUntil 0-0-5 08:00 && Task goes here.

0=Success            1=Time out expired   2=Argument error
3=CTRL-C             4=CTRL-BREAK         5=Window close
6=Logoff             7=Shutdown.