condition mean min max 4 h after light 1.6 1.6 1.6 8 h after light 2.9 1.9 3.9 12 h after light 6.35 3.2 9.5 4 h after dark 1.05 0.8 1.3 8 h after dark 3.95 2.0 5.9 12 h after dark 17.6 4.0 31.2