10 0 Total cloud amount less than 1/8 21 1 Total cloud amount at least 1/8, with either 1/8 to 4/8 above or 1/8 to 4/8 below, or combinations thereof 32 2 Cloud amount more than 4/8 above and 0 to 4/8 below 43 3 Cloud amount 0 to 4/8 above and more than 4/8 below 54 4 Cloud amount more than 4/8 above and more than 4/8 below 65 5 Chaotic sky, many undefined layers 76 6 In and out of clouds, Instrument Meteorological Conditions 25 percent of the time 87 7 In and out of clouds, Instrument Meteorological Conditions 50 percent of the time 98 8 In and out of clouds, Instrument Meteorological Conditions 75 percent of the time 109 9 In clouds all the time, continuous Instrument Meteorological Conditions 1115 15 Missing value 12