This addon mod allows to manually set and freeze a certain hour in-game.
To install, place folder "Quests" in your MAIN game "Database" folder.
The default in-game hour is set to 20 ("eternal sunset"). To set a different one: 
1. Open the modified "Quests" folder. Inside you will see many .QST files, each with a specified frozen hour.
2. Pick a file with your desired hour (for example "init - set up all acts_(hour = 12).qst"), copy it and rename it to just "init - set up all acts.qst" (which is the .QST file the game actually reads), replacing the default one. 

I haven't tested all hours, but they should work without problem. See screenshot on how to make such a mod with the Quest editor.

Have fun! :)

N66