2014 Flagstaff Nighttime Cloudiness Summary Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Yr (nights) Photometric 6 4 6 6 8 17 1 4 8 9 13 2 84 Monthly Average: 7.0 Partial 9 3 7 10 9 3 0 4 7 7 3 7 69 Monthly Average: 5.8 Spectroscopic 4 5 6 5 6 7 6 4 4 5 6 1 59 Monthly Average: 4.9 Cloudy 12 16 12 9 8 3 24 19 11 10 8 21 153 Monthly Average: 12.8 ------------------------------------------------------------------------------- Clear Hours 147 62 111 105 101 133 7 57 117 134 172 77 1223 Monthly Average:101.9 Clear+Dark Hours 54 48 41 47 70 72 5 30 72 76 74 52 641 Monthly Average: 53.4 Mean Consec 1.2 1.0 1.2 2.0 1.6 4.3 1.0 1.3 1.6 1.8 2.2 1.0 Monthly Average: 1.7 Max Consec 2 1 2 2 3 6 1 2 2 2 4 1 Monthly Average: 2.3 ------------------------------------------------------------------------------- Definitions: Photometric - cloudfree dusk-to-dawn. Partial - at least 3 consecutive cloudfree hours during the night. Spectroscopic - less than about 1 mag. extinction throughout the night. Cloudy - cloudy. Clear+Dark Hours = photometric hours with moon absent. Mean Consec = mean number of consecutive photometric nights during the month. Max Consec = maximum number of consecutive photometric nights during the month.