condition mean min max 4 h after light 6.5 6.5 6.5 8 h after light 7.25 5.0 9.5 12 h after light 6.85 5.3 8.4 4 h after dark 10.4 10.3 10.5 8 h after dark 11.600000000000001 6.1 17.1 12 h after dark 5.9 4.9 6.9