Most football fields have end zones in the north and south portion of the stadium, but not all. As of 2008, as many as 70 percent of professional football fields in the U.S. faced north-south. That still leaves quite a handful of fields that do not face in this direction. And when one takes into account that no matter your location, the sun rises in the east and sets in the west, playing on a field that faces in the same direction can be quite debilitating when the glaring sun is in your eyes.
The NFL has no rules or guidelines regarding stadium orientation. And with many newer stadiums sporting decks high enough to help block the sun, this north-south trend seems to be fading, as many stadiums are likely being built simply to fit the real estate. Aside from the sun, typical wind direction for a given location is another weather-related issue that players will have to adjust to.