Well, that's not quite true. Round here at the minute night kind of gently drifts down - and then disappears again before you know it.
When we first moved in (last summer), we got some super-mega blackout Velux blinds because it was way too light in the middle of the night.
But with the blinds down, it is way too dark and we never wake up naturally in the morning
So now we compromise by leaving them open a crack...