The precise date depends also on the moon, which is why it is not a fixed date. The rising is also affected by latitude, being later on any given day for viewers further south. It occurs most often in June.
Watch for ceremonies and a big celebration on Maori Television.
It appears to correspond to the obsolete Makahiki festival of Hawaii.
2013 - June 10th
2014 - June 28th
2015 - June 18th