condition mean min max 4 h after light 5.6 5.6 5.6 8 h after light 5.55 1.4 9.7 12 h after light 2.25 1.4 3.1 4 h after dark 17.3 4.3 30.3 8 h after dark 3.9 3.0 4.8 12 h after dark 1.45 1.2 1.7