Hi,
according to Metservice NZ, their rain radar is updated every 7.5 minutes.
Looking at NZ rain radar on Windy, switching on animation, there hardly any change, whereas when I navigate over to Australia, I see a nice smooth animation of rain fronts moving.
Ref: https://www.metservice.com/maps-radar/rain/radar?range=300&tab=real-time
Is there an update issue with NZ rain radars?