Sand, sea and sun are all part of the great Auckland summer but so too are storms, thanks largely to La Niña, part of the global climate cycle known as the El Niño-Southern Oscillation (ENSO).
The ENSO cycle is driven by fluctuations in the water temperature in the Pacific Ocean, coupled with atmospheric changes. El Niño and La Niña are the extreme phases of the ENSO cycle; between these two phases is a third called ENSO-neutral, when the atmosphere and oceans are influenced by other climate drivers.
El Niño/La Niña occur every two to seven years and the impact of each depends on its intensity. During El Niño, New Zealand tends to experience stronger or more frequent winds from the west in summer, which can result in drier conditions in eastern areas and more rain in the west. In winter months, the winds tend to blow more from the south, causing colder temperatures across the country.
La Niña on the other hand, tends to bring warmer than average ocean and air temperatures for New Zealand. This summer, the forecasts suggest we’ll experience a moderate to strong La Niña system and the most intense that we’ve seen in 10 years. For Auckland, this will mean a more humid summer with heavy rain bursts and a chance of cyclones. It’s been a while since Auckland has experienced weather like this and there are a few simple things we can all do to be summer storm-ready.