condition mean min max 4 h after light 10.4 10.4 10.4 8 h after light 5.55 5.1 6.0 12 h after light 13.4 3.7 23.1 4 h after dark 4.3 2.3 6.3 8 h after dark 9.7 6.3 13.1 12 h after dark 14.65 6.2 23.1