2013 Flagstaff Nighttime Cloudiness Summary


                 Jan  Feb  Mar  Apr  May  Jun  Jul  Aug  Sep  Oct  Nov  Dec  Yr
                              
                                        (nights)
           
Photometric       11   10    6   12
                                                           Monthly Average:

Partial            6    6    4    6
                                                           Monthly Average:  

Spectroscopic      3    3    5    5
                                                           Monthly Average:  

Cloudy            11    9   16    7
                                                           Monthly Average: 

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Clear Hours      180  154   85  134
                                                           Monthly Average:

Clear+Dark Hours  85   74   35   42
                                                           Monthly Average: 

Mean Consec      2.8  2.5  1.2  2.4
                                                           Monthly Average:  

Max Consec         6    4    2    7
                                                           Monthly Average:  
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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.