Washing at night means that my hair is bone dry when I wake up. All I have to do is scrunch the crunch a bit. I can see exactly what the 'finished product' looks like, and I can always make alterations then. Also, because my hair is on the pillow, it curls up more. Lastly, because I'm indoors and asleep, I'm not touching my hair, and it's not being affected by weather or anything.