midnight-delay

midnight-delay is a variable defined in `midnight.el'.
Its value is

3600

Documentation:
The number of seconds after the midnight when the `midnight-timer' is run.
You should set this variable before loading midnight.el, or
set it by calling `midnight-delay-set', or use `custom'.
If you wish, you can use a string instead, it will be passed as the
first argument to `run-at-time'.

You can customize this variable.