Why is Antarctica so cold ?

Well, there are some obvious 'answers' to this, but the reality is that there is a combination of factors which make this continent so cold (and colder than the Arctic which is at the same latitude.
The tilt of the Earth has something to do with it of course.

This means that there is no sun for months at a time during the winter months.
This diagram illustrates the day length (click for large version)

There's also the angle at which the sun passes through the atmosphere.

And the albedo: the amount of heat that is reflected from the snow and ice that make up the surface.

Plus, the height above sea level: the South Pole is 2800m high, and the mountains and ice sheets combine to reach a height of almost 5000m above sea level.

Can you use these (and other) factors to help explain the temperature distribution shown in this diagram:

Images from Wikimedia Commons