With wet weather starting today and worsening tomorrow, drivers in the top half of the North Island are urged to take extra care on the roads.

After an extended period of good weather, the initial rainfall can make roads extremely slippery due to the build-up of dust, dirt, and oil on the road surface, Waka Kotahi NZ Transport Agency says.

Drivers are advised to reduce speeds and increase following distances, it said in a statement.

MetService has issued heavy rain and strong wind watches for Auckland, Northland, Coromandel and Taranaki.

Severe Weather Update

Heavy rain and blustery northerly winds are on the way!

The largest accumulations are forecast for the northwest of the South Island where 350-450mm of rain is forecast. This area could still be upgraded to a Red Warning. pic.twitter.com/fZnvCRhmQ8

— MetService (@MetService) April 1, 2025

Rain is also forecast to become widespread tomorrow around the rest of the region - in the Waikato, especially at Waitomo, and in the Bay of Plenty, said a spokesperson said.

The severe weather is expected until late Friday afternoon.

“Road users should be aware that the risk of slippery roads is highest shortly after the rain begins, but the conditions can last for some time. Take extra care on curves and when braking and steering,” said an NZTA the spokesperson said.

“The term ‘summer ice’ [is] used to describe these conditions and it’s not unlike the black ice you get in winter, in that the road is really slippery, but it isn’t visible to drivers.

“Heavy rain also increases the risks of slips and localised flooding. Road users must be prepared for these hazards while weather warnings are active.

“Bad weather can also see roads closed at short notice.”

Drivers are encouraged to check road and weather conditions before they travel. journeys.nzta.govt.nz

Stay safe and adjust your driving to the conditions. For more information, visit the NZTA website about summer ice. https://www.nzta.govt.nz/safety/driving-safely/driving-to-the-conditions/summer-ice/