Story: Climate

Southern Oscillation Index, 1955–2005

Southern Oscillation Index, 1955–2005

The most accurate way of identifying El Niño or La Niña weather phases is to measure the annual air-pressure variation across the Pacific (between Tahiti in the east and Darwin in the west). These measurements are known as the Southern Oscillation Index. A variation of below -1 indicates an El Niño weather pattern. When the variation is above +1, La Niña is active.

Using this item

Te Ara - The Encyclopedia of New Zealand

This item has been provided for private study purposes (such as school projects, family and local history research) and any published reproduction (print or electronic) may infringe copyright law. It is the responsibility of the user of any material to obtain clearance from the copyright holder.

Source: NIWA – National Institute of Water and Atmospheric Research

All images & media in this story

How to cite this page:

Brett Mullan, Andrew Tait and Craig Thompson, 'Climate - New Zealand and global climate patterns', Te Ara - the Encyclopedia of New Zealand, http://www.TeAra.govt.nz/en/graph/7783/southern-oscillation-index-1955-2005 (accessed 26 June 2019)

Story by Brett Mullan, Andrew Tait and Craig Thompson, published 12 Jun 2006