I sometimes have difficulty sleeping as a result of the twilight - no matter which way I shift my bed while home for the summer, I can still see the orb of light slowly moving across the sky from sun"set" to sun"rise". Don't get me wrong, I love the fact that it's light until beyond 11 up here, great for BBQs, parties, sport etc - but I do like to have pitch darkness while sleeping.
Midwinter on the other hand