Making night... a little more... dark?

Is there any way to set how dark it is at nighttime or achieve this effect?

good questoin, no unfortunalty i am almost postive there isn't, it's not under Gameplay constants, so chances are, there isn't
Sorry

~Duff

what I did for my map is, I made a trigger for when game time is 18:00 I set the sky to none and fog to black. I make the fog start close at around 900 and end at around 5000. When it gets to 6:00 game time I set the day sky(what ever you want) and set the day fog ( what ever you want). I can make a test map of it if you want.

Try making it start at 0 for a darker look

take a fade filter and have it fade in when its night time. set it to a white filter at 0,0,5 for colors with 50% transparancy. if thats too dark than change to 60/70% or try making a more lighter blue. hope this helps