You might have booked a scenic flight, boat trip,… which are weather dependent. The weather is very unpredictable in NZ! Try to have a bad weather replacement activity in case the trip gets cancelled. And try to have at least 2 days at those locations, so you might be able to do the trip the next day… We had 4 out of 7 excursions cancelled because of the weather, including a glacier heli-walk and an active vulcano walk .