condition mean min max 4 h after light 1.9 1.9 1.9 8 h after light 5.15 2.8 7.5 12 h after light 10.1 1.5 18.7 4 h after dark 3.8 1.9 5.7 8 h after dark 2.3 1.4 3.2 12 h after dark 10.55 4.0 17.1