condition mean min max 4 h after light 3.8 3.8 3.8 8 h after light 5.4 2.2 8.6 12 h after light 6.1000000000000005 1.8 10.4 4 h after dark 1.75 1.7 1.8 8 h after dark 8.8 1.8 15.8 12 h after dark 10.950000000000001 1.8 20.1