Thanks. I emptied these folders but nothing changed.
Here are two tracks showing the difference between day and night time. Same mission and weather parameters, except for the time (2.30pm and 0.30am)
During day time, in the clouds, you can barely see the line of tankers at 12 o'clock.
During night time, with NVGs, you can see EVERYTHING clearly.
I also tried with the Mirage NVGs, same results, so either it's my computer or it's DCS World related.
Note: I'm on the Open Beta Bad Weather Visibility.trk Bad Weather Night Visibility with NVGs.trk