In this study we describe an innovative method to determine potential sites for optical and infrared astronomical observations in the Andes region of northern South America .
The method computes the Clear sky fraction ( CSF ) from Geostationary Observational Environmental Satellite ( GOES ) data for the years 2008-12 through a comparison with temperatures obtained from long-term records of weather stations and atmospheric temperature profiles from radiosonde .
Criteria for sky clearance were established for two infrared GOES channels in order to determine potential sites in the Andes region of northern South-America .
The method was validated using the reported observed hours at Observatorio Nacional de Llano del Hato in Venezuela .
Separate CSF percentages were computed for dry and rainy seasons for both , photometric and spectroscopic night qualities .
Twelve sites with five year averages of CSF for spectroscopic nights larger than 30 % during the dry seasons were found to be suitable for astronomical observations .
The best site with ( 220 \pm 42 ) spectroscopic clear nights per year is located in the Andes of Venezuela ( 70 ^ { \circ } 28 ’ 48 ” W , 9 ^ { \circ } 5 ’ 60 ” N ) at an altitude of 3480 meters .
Lower quality regions were found in Sierra Nevada de Santamarta and Serranía del Perijá with ( 126 \pm 34 ) and ( 111 \pm 27 ) clear nights per year , respectively .
Sites over the Andes are identified in Norte de Santander with ( 107 \pm 23 ) and in the north-east part of Boyacá with a mean of ( 94 \pm 13 ) clear nights per year .
Two sites at low latitude located in Ecuador with more than 100 clear nights per year and with similar seasonal CSF percentages were also identified .
Five year evolution suggest a possible correlation between the lowest percentages observed during the rainy seasons of 2010 and 2011 with positive values of the Southern Oscillation Index .