condition mean min max 4 h after light 2.6 2.6 2.6 8 h after light 3.55 2.3 4.8 12 h after light 2.45 2.4 2.5 4 h after dark 3.15 2.8 3.5 8 h after dark 4.0 2.6 5.4 12 h after dark 4.1 2.3 5.9