condition mean min max 4 h after light 3.9 3.9 3.9 8 h after light 3.9 2.5 5.3 12 h after light 3.65 3.4 3.9 4 h after dark 4.7 4.4 5.0 8 h after dark 13.35 4.0 22.7 12 h after dark 5.5 5.1 5.9