What capital is the most southern capital in the world?

This distinction belongs to Wellington, New Zealand. Wellington is the cultural capital and geographical center of the country. Wellington is the only world capital located in the roaring 40s latitudes. It was the first world capital to welcome the 3rd millennium.

Specifically, Wellington is New Zealand's political center, housing Parliament and several key governmental offices and departments as well as the bulk of the foreign diplomatic missions. It is also an important center for the film and theater industry.

In 2014, Wellington had the 12th best quality of living in the world according to the Mercer Quality of Living Survey which usually evaluates and ranks 221 cities from Vienna to Baghdad on quality of life.