Just about everybody has heard of El Niño, which has been known to affect weather systems in Australian, and tends to cause droughts and increased fire risk.
As of 10 September 2026, a strong El Niño has developed. Indeed, the latest assessment by the US National Oceanic and Atmospheric Administration (NOAA) gives a >90% chance of a very strong El Niño1. How this will affect Australia is yet unclear, because there are other factors to be considered.
Another part of this system which has an effect on Australia’s weather patterns is the Southern Oscillation. This refers to a bimodal variation in sea level air pressure between observation stations at Darwin, Australia and Tahiti. It is quantified as the Southern Oscillation Index (SOI), which is a standardised difference between the two pressure measurements. Normally, lower pressure over Darwin and higher pressure over Tahiti encourages a circulation of air from east to west, drawing warm surface water westward and bringing rain to Australia and the western Pacific. When the pressure difference weakens, which is usually coincidental with El Niño conditions, parts of the western Pacific, including Australia experience severe drought, while in equatorial South America, heavy rain can cause severe flooding2.
El Niño and the Southern Oscillation are together referred to as ENSO. However the strength of ENSO doesn’t necessarily mean an extreme Australian drought or fire season, as the effect is also dependent on the Indian Ocean Dipole (IOD) and the Southern Annular Mode (SAM), as well as local sea surface temperatures (SST)3.
The IOD refers to the difference in sea surface temperatures of the Tropical western and eastern Indian Ocean. The IOD is one of the key drivers of Australia’s climate and can have a significant impact on agriculture. This is because events generally coincide with the winter crop growing season4.
The SAM, refers to the (non-seasonal) north-south movement of the strong westerly winds that blow almost continuously in the mid- to high-latitudes of the southern hemisphere. This belt of westerly winds is also associated with storms and cold fronts that move from west to east, bringing rainfall to southern Australia5.
Currently, a strong El Niño is firmly established, with further intensification during Spring likely reaching a level stronger than the strongest events since 1950 when reliable records began. The Southern Oscillation Index (SOI), a measure of the atmospheric component of the ENSO, rose over the second half of August, but remains strongly negative, well below the El Niño threshold3.
The Indian Ocean Dipole (IOD) is currently neutral, having eased back from positive into the neutral range over August. However, modelling continues to suggest a positive IOD could develop during the Spring, although the forecast magnitude of the event has decreased in recent model runs3.
The Sea Surface Temperature (SST) analysis for last week of August shows warmer than average waters around most of Australia and mostly near average temperatures to the north. Waters are especially warm along the southern New South Wales and eastern and southern Tasmania coasts, peaking at around 2–3 °C above average. These are forecast to warm over the Spring, especially in Australia’s west3. Globally (60°S to 60°N), daily SSTs have seen the warmest August on record, sitting at 1.32 degrees C above the 20th Century average6.
The long range forecast in Australia for October to December indicates that there is likely to be above average rainfall across much of the west, central and northeast of the continent, and below average in the southeast. Both daytime and nighttime temperatures are likely to be above average, with a 60% chance of unusually high maximum temperatures, and unusually high minimum temperatures7.
This strong El Niño is already causing major problems for many people. The Peruvian anchovy catch has failed due to warmer waters in the eastern Pacific causing the anchovies to search for food in deeper, colder waters. Drought conditions in central America have slowed shipping in the Panama Canal, which uses fresh water to fill its locks for each ship to pass. Smallholder farmers in Guatemala, Honduras and El Salvador have reported crop losses. Indonesia has seen an above average beginning of the wildfire season. Dry weather in parts of southern and eastern Africa, coupled with high prices for fuel and fertiliser caused by the idiot Trump’s war with Iran, is threatening food security8.
The big question is how global warming will affect the influence of this El Niño. There are some indications that the effects have started to change. For instance, El Niño events were associated with warmer temperatures in south Asia and northeastern Africa between 1960 and 1990, but since then those parts of the world have had cooler temperatures. Over the same interval, Europe used to be colder during El Niño events; now it is getting warmer8. The Boreal Summer has seen one of the worst fire seasons on record for parts of Europe9. Such changes could make it much more difficult to predict, and therefore prepare for, likely changes in the weather patterns.
Sources
- https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml
- https://www.ncei.noaa.gov/access/monitoring/enso/technical-discussion
- https://www.bom.gov.au/climate/enso/?ninoIndex=nino3.4&index=rnino34&period=weekly
- https://www.bom.gov.au/climate/iod/
- https://www.bom.gov.au/climate/sam/
- https://www.ncei.noaa.gov/news/global-climate-202608
- https://www.bom.gov.au/climate/outlooks/#/overview/summary/
- https://www-nature-com.simsrad.net.ocs.mq.edu.au/articles/d41586-026-02826-5
- https://www.euronews.com/business/2026/08/13/wildfires-in-europe-is-2026-already-the-worst-year-on-record