There was significant flooding across Northland in April, including the floodwater pictured on SH1 in the Far North, near Umawera, during ex-Tropical Cyclone Tam.
There was significant flooding across Northland in April, including the floodwater pictured on SH1 in the Far North, near Umawera, during ex-Tropical Cyclone Tam.
It may come as no surprise, but last month was one of the wettest Aprils on record for many Northland towns as big storms, including ex-Tropical Cyclone Tam, battered the region.
The region was hit by three big rain events, including ex-Tropical Cyclone Tam last month, causing widespread flooding, slips that closed roads - including SH1 over the Mangamukas twice and the Brynderwyn Hills, south of Whangārei.
The full extent of the rainfall has been illustrated in Niwa’s monthly climate summary for April, that reveals record downpours across Northland.
Six locations across the country observed their wettest April on record, including three in Northland, Niwa climate scientist Gregor Macara said.
Kaitāia was New Zealand’s wettest location compared to normal. The town received 420mm of rainfall, more than four times its normal for April, which was its wettest April since records began in 1948.
New Zealand’s driest location compared to normal was Wairoa, which received 47 mm of rain during April (36% of its April normal).
Kerikeri also recorded its wettest April on record, with 519mm - three and a half times its normal for the month - its highest since records began there in 1935.
Whangārei had its wettest April on record too, with 403mm - almost four time the normal - and the highest in April since records began there in 1937.
Dargaville recorded 218mm - more than double the norm - its second highest April rainfall on record since 1943.
Kaitāia also recorded its highest one-day rainfall total for April: 132mm on April 3.
Kerikeri recorded its third-highest April one-day rainfall of 123mm the same day.
Macara said April 2025 was characterised by lower-than-normal mean sea level pressure (MSLP) to the northwest of the country and higher-than-normal MSLP to the east of the country.
“‘This produced more northeasterly airflows than normal, bringing sustained warm temperatures and several heavy rain events over the course of the month. This included the arrival of ex-tropical cyclone Tam around mid-April, which caused flooding, power outages and coastal erosion for parts of Northland, Auckland, Coromandel and the Bay of Plenty.
From April 3 3 to 4, an atmospheric river contributed to heavy rainfall and surface flooding for western and northern parts of the South Island, and northern parts of the North Island. Areas of surface flooding and power cuts were reported in Northland. Roads affected by surface flooding and debris included Diggers Valley Rd in Herekino, and Ōruru, Peria, Kenana, Omaunu and Kohumaru roads.
Heavy April rain twice caused slips that closed SH1 over Mangamuka Gorge, in the Far North. The storms meant one of the wettest Aprils on record for many Northland towns.
From April 16, ex-tropical cyclone Tam travelled south and impacted much of New Zealand over the following days. The system was associated with a combination of strong winds, periods of heavy rain, and storm surges causing coastal erosion, with the greatest impacts observed in Northland, Auckland, the Bay of Plenty, and Coromandel.
The storm brought down trees, flooded roads across Northland and left thousands without power.
The highest wind gust for the month was 156km/h at Cape Reinga on April 17.
The month also contained some unseasonably warm weather across Northland, Kaitāia and Whangārei having their second-highest April mean air temperature ever of 19.1C and 18.5C respectively.
