condition mean min max 4 h after light 2.6 2.6 2.6 8 h after light 7.0 4.3 9.7 12 h after light 8.85 5.1 12.6 4 h after dark 4.45 3.4 5.5 8 h after dark 4.55 3.3 5.8 12 h after dark 6.65 4.2 9.1