Can the 'top' view be rotated by 180° around the Z-axis by default? Is it somehow possible to have the top view (Numpad 7) rotated by 180 degrees by default?

I can get the view I'm after using the key combination Numpad 7 then 12 x Numpad 6 (or 12 x Numpad 4).

I was hoping that there is some option or setting to rotate this default top-view orientation by 180° around the Z-axis?
There is no way to customize the default orientation as far I know (maybe some clever person could write a script and assign it to the numpad keys)

As an alternative you can change the default scene.

Rotate the view to where you need it, then press Ctrl+U to save the startup file. That way blender will always open with your preset view.

Make sure that the Load UI (load User Interface) box is enabled on the user preferences>file>load &amp; save section.

You could also create custom layouts and save those as part of the startup file, that way instead of changing the views, change to the layout that has the orientation you want to use CtrlLeft or CtrlRight

See this related post: Can screen layouts be locked?