66½oN/S are the Arctic and Antarctic circles; above that latitude there will be days in the winter when the sun will not rise.   Anything above 64½oN/S is in ‘the land of the midnight sun’ and there will be days in the summer when the sun remains above the horizon and does not set.   To see a sun rise and a sun set every day the observer on the ground must be at a latitude below 64½oN/S.