What is the annual average number of hours of sunlight in Raleigh?
Posted April 18, 2007
MIKE MOSS SAYS: Suzi, There are a couple of factors to consider here. If we define "sunlight" as anytime a portion of the sun is above the horizon and the sky is clear, the if there were no cloudiness we would have around 4580 hours of sunlight a year in Raleigh (note that this is more than half the hours in the year, based on a real rough quickie estimate on my part because of the eccentricity of Earth's orbit and the effect of refraction and our manner of defining sunrise and sunset, both of which increase hours of "daylight" compared to hours of "darkness"). There are climatological estimates available fromthe National Climatological Data Center of the effect of cloud cover available which indicate Raleigh should average about 58% of the sunshine that would be available if skies were always clear. Based on this figure, we should average about 2660 hours of "sunlight" a year.