Answer:
The earth revolves around the sun in a plane called the ecliptic.
The poles of the earth are at an angle of about 23.5 deg from the ecliptic.
If the north pole is tilted at 23,5 deg towards a perpendicular to this plane (ecliptic) the south pole will be tilted at 23.5 deg away from this plane and will receive the least amount of sunshine.
This is called the summer solstice in the northern hemisphere. and occurs around June 21.