I was wondering if any of you have first hand account with LED lights in a up lighting application like flag poles or wall washing. LED lights give off significantly less heat then their MH/HPS counterparts. With any fair amount of snow, I envision snow accumulation on the lens during the day and with the lack of heat from within, it would take hours if not days to melt any snow away even if the light is well above ground level. Can anyone shed and light (no pun intended) on the matter?

I think you are right about the problem. There is a problem with LED traffic lights.

http://blogs.cars.com/kickingtires/2009/12/led-traffic-lights-cant-melt-snow-ice.html