The best time of the year to visit Dunedin is January or February. In January it is warm and quiet, because the students are out of town. That means there is not a lot of people around, you can see all the attractions quietly (including the University Clock tower) without having to fight through the hordes of students. However if you want to have a bit more action, go in February. The students are all coming back in Feburary, Orientation Week starts at University and it is still warm. Any bars that are closed over the summer break will reopen and there will many events going on.