As to the morning business. The game engine, virtually certainly in a .dll and hence beyond the access of a mere mortal modding chimp like me, generates a fog that commences in morning twilight, reaching peak density a bit after sunrise. I've always hated it. I wish the player had some control at least. I've searched the classes to see if this could be possible; no dice.
This is one aspect we have to live with. 😞
The rapidity of change is accentuated for maps at tropical latitudes, where twilight is of shorter duration due to the nearly vertical path of the rising (or setting) Sun. At higher latitudes, where the Sun rises/sets at a shallower angle, twilight lasts longer and so the changes in lighting and fog density occur at a more languid pace.
There is another twilight issue that grinds my gears. The sky brightness, at a certain solar depression angle, makes a quite marked change. And it's out of sync with the landscape lighting as set in Sun.class, resulting in a short period of ridiculously bright clouds in a dark sky.
I'd be tempted to donate a lesser used organ if only I could access the sky twilight brightness and fog code. 😉