Rotorua Tauranga Heavy Rain: 40-Hour Warning Update

If you live in Rotorua or Tauranga, you’ve probably been watching the rain radar closely this week. A 40-hour heavy rain warning had forecast intense downpours, but the actual totals so far tell a more measured story.

Tauranga rain recorded so far (Mar 26): fraction of predicted 40-hour total ·
Rotorua rain recorded (Mar 26): 8.6mm of predicted 48.4mm ·
Heavy rain warning level: Red warning lifted; Heavy Rain Watches continue for Westland and Tararua ·
Affected region: Bay of Plenty, including Rotorua and Tauranga

Seven key figures stand out from the official data, one pattern: the gap between forecast and observed rainfall is significant, especially in Rotorua.

The table below lays out the key numbers from this event.

The implication: the system delivered intense rain in pockets but left the main urban centres drier than forecast.

Why is it raining so much in New Zealand right now?

La Niña influence

• Persistent low-pressure systems are driving moisture-laden air from the subtropics over the North Island (NIWA (national climate research institute)).
• A La Niña pattern has been active, favouring above-normal rainfall for northern and eastern areas of New Zealand.

Subtropical moisture flows

• A deep trough interacting with warm sea-surface temperatures north of the country has fed a conveyor belt of moisture into the Bay of Plenty (NZ Herald (major national news outlet)).
• MetService forecasts peak rain rates of 15 to 20 mm/h, increasing to 25 to 40 mm/h from early Friday morning (Western Bay of Plenty District Council).

What is the red warning in New Zealand?

MetService warning levels explained

• Red is the highest alert for dangerous weather, reserved for events expected to cause significant disruption and risk to life (Western Bay of Plenty District Council).
• Orange warnings indicate moderate to heavy rain that may cause flooding and disruption, but with lower risk than red.

Red warning vs orange warning

• For the current event, MetService initially issued an orange warning for Bay of Plenty west of Whakatāne, spanning 29 hours from 8pm Thursday 26 March to 1am Saturday 28 March (Western Bay of Plenty District Council).
• There was a high chance the orange warning could be upgraded to red (Western Bay of Plenty District Council).
• A red warning was eventually issued for parts of the region, but it was later lifted (Radio 1XX (local radio station)).

The pattern: despite the red warning being lifted, the risk of severe localised flooding remains active.

Is it going to rain in Tauranga today?

48-hour rain radar Tauranga

• Radar imagery shows active bands moving across the western Bay of Plenty, with the heaviest showers currently near Tauranga (Radio 1XX).
• MetService expects another 50 to 80 mm of rain on top of what has already fallen, according to the same warning (Radio 1XX).

MetService Tauranga forecast

• Today’s recorded rainfall is still well below the predicted high-end of the 40-hour total (NZ Herald).
• Temperatures remain cold: Tauranga is at 6.1°C (feels like 5°C), Rotorua at 3.6°C (feels like 1°C) (Radio 1XX).

The gap between predicted and recorded rainfall in Rotorua and Tauranga is a reminder that weather forecasts, even with advanced models, can overestimate the intensity of a system. But the 182mm that fell at Matatā shows the potential for flash flooding remains. For residents of Tauranga and Rotorua, the smart move is to keep the radar on and stay informed – the next band could bring the deluge the warning promised.