condition mean min max 4 h after light 20.1813 18.8404 21.5222 8 h after light 12.59715 11.8539 13.3404 12 h after light 7.49874 6.89311 8.10437 4 h after dark 5.034565 4.92948 5.13965 8 h after dark 7.684635 7.47951 7.88976 12 h after dark 13.69465 13.5111 13.8782