A table is presented that gives the total number of hours in the year during which the sun’s altitude exceeds a given value h, for h = 0–88° in 2° increments and for latitudes from the Equator to the North Pole in 2° increments. The table also gives corrections to these figures for the effect of atmospheric refraction and the total hours of daylight at each latitude.
R. S. McDowell, "Solar altitude frequency tables," Appl. Opt. 22, 563-567 (1983)