Board Thread:Warhammer 40k General Discussion/@comment-5846164-20121209201723/@comment-5852232-20121210133117

^^ That, and we don't have to remind you some ork tribes are dumber/more superstitious than others. Considering they think red makes you go faster, I could see some of them being afraid of fighting in the dark :p

But yeah, its probably an author trying to explain why it had to take place at night ;)