condition mean min max 4 h after light 15.442 15.101 15.783 8 h after light 16.10895 14.837 17.3809 12 h after light 15.5947 14.661 16.5284 4 h after dark 20.3158 18.4896 22.142 8 h after dark 17.8596 17.3123 18.4069 12 h after dark 18.3354 18.1864 18.4844