NIWA is warning an El Niño could be declared in the next few weeks with the climate system likely to be among the strongest El Niño’s declared in the past 80 years bringing a heightened risk of drought and warnings of fire danger. NIWA meteorologist Ben Noll said data suggests this El Niño is among the five strongest occurring in the past eight decades. It would be the first of its kind in NZ since 2016 and is developing alongside a positive Indian Ocean Dipole, another climate driver reducing the chance of tropical moisture plumes.

Noll expects El Niño to develop by the end of September with a shift in the frequency and intensity of westerly winds, spelling below-normal rainfall and frequently warm temperatures for the east of both islands. Noll said Canterbury, eastern Marlborough, northern Otago, Wairarapa and Hawke’s Bay were likely to experience conditions in contrast to previous spring and summer weather.