Is there a point (USDA Agricultural zone) at which the heat loss in the winter time through north facing windows is out weighed by the gain in the circulation of cool air during the summer time. At what point as you move from north to south does it become worth it to have north facing windows? (Reverse this for the southern hemisphere as you move from south to north.)
There isn't a single point. Circumstances vary widely, and depend on the detail of individual design. There are, however, well-established mechanisms to evaluate any single building.
As for using North-facing windows in the Northern hemisphere for cooling, that's a pretty bad way to do things. Preventing solar gain in the first place is far more effective, for example by using external window shutters or roof overhangs:
picture courtesy of PassivDesign.org
Without regard to individual site qualities; those living north of the equator but south of the Tropic of Cancer receive a positive net benefit from northern glazing. The benefit is so small to be meaningless. For those living in the tropics window orientation is decided exclusively by site characteristics.
Of course those living south of the Tropic of Capricorn definitely want north facing windows!