I believe that tourists should come in winter.
In winter there's hot water pool in rotorua the thermal pool. It would be so calming and relaxing. If the tourist is not a psychocentric and instead is a Allocentric (definitions will be after the text) Then the best thing they could do is go skiing and snowboarding at ruapehu. It is an incredibly fun activity to do in the winter. If the tourist is more of a celebrational person then theres always maori new year. They do fireworks and have large feasts that you can buy. Not only that but on some events they even put up a little show. Lastly if the tourist just has nothing to do and there attracted to the ocean, they can always go whale watching. It's always so magnificent watching the whales swim. It only depends on what the tourist likes.
Definitions:
Psychocentric: A calm and steady person
Allocentric: A extreme and adventurous person