condition mean min max 4 h after light 1.6 1.6 1.6 8 h after light 5.85 5.8 5.9 12 h after light 3.3 3.1 3.5 4 h after dark 2.4000000000000004 2.2 2.6 8 h after dark 3.1999999999999997 2.3 4.1 12 h after dark 4.2 3.7 4.7