condition mean min max 4 h after light 4.8 4.8 4.8 8 h after light 5.45 5.0 5.9 12 h after light 4.45 3.4 5.5 4 h after dark 7.55 4.6 10.5 8 h after dark 4.55 3.8 5.3 12 h after dark 6.2 4.9 7.5