Australia’s Mining and Resources sectors are bracing for a wet season shaped by one of the most rapidly developing El Niño events on record.
Looking back at how the strongest El Niño events in Australian history have played out, it becomes apparent that mining operations in Australia should be planning for a later monsoon onset, a slower start to the wet season, and a quieter cyclone season than usual.
A record-breaking start
The El Niño Southern Oscillation index flipped from La Niña phase to El Niño in a matter of months during 2026, with the Bureau of Meteorology’s relative Niño3.4 index climbing from -0.92°C in January to +1.84°C in August. That is the fastest January-to-August strengthening rate in 126 years of records- a jump of +2.76°C, well ahead of the previous record of +2.17°C set in 1997.
Historical analogues suggest the event is still several months from its peak, which typically falls between November and January. Based on how comparable events (1902-03, 1982-83 and 1997-98) evolved after August, this El Niño could strengthen by another 0.5–1.5°C before peaking, potentially placing it among the strongest events ever recorded. The current record stands at +2.65°C (reconstructed relative Niño3.4 index), set during the 1902-03 event, with 1982-83 (+2.60°C) and 2015-16 (+2.39°C) rounding out the top three.
The image below compares the monthly development of the 2026 event against these strongest analogues on record. At +1.84°C in August, 2026 is tracking below all of them at the same point in their development – meaning this event likely hasn’t peaked yet, with further strengthening typical before a November-January peak, followed by the sharp autumn/winter decline that all major El Niño events eventually share.
Image: Monthly relative Niño3.4 index evolution of the 2026-27 event compared with some of the strongest El Niño events on record. Source: DTN
What does this mean for Northern Australia’s monsoon timing?
For operators across the Pilbara, the Kimberley, the Northern Territory and North Queensland, the timing of the monsoon trough is one of the most consequential seasonal variables in the operating calendar. It governs haul road conditions, tailings and water management, dust suppression planning, rail and port loadout scheduling, and the workforce and logistics arrangements built around the wet season shutdown period.
During El Niño years, the monsoon typically arrives later than the average onset date of late December, with some of the more extreme delays reaching mid-to-late January. El Niño years also typically bring below-average rainfall across northern Australia during the early wet season (October–December), before conditions move closer to average once the monsoon eventually arrives. Cyclone activity follows the same pattern: El Niño years typically bring a below-average number of tropical cyclones across the Australian region, with the first cyclone to cross the coast also tending to occur later than the typical early-January timing.
El Niño has a well-documented tendency to delay the northern rainfall onset and push back the arrival of the monsoon trough – and the effect has been most pronounced during the strongest events on record, as shown below.
The mechanism behind this is well understood: El Niño tends to keep the tropical Pacific’s rain-bearing convection anchored further east, while cooler waters and increased subsidence over northern Australia suppress the cloud and moisture buildup needed to trigger the monsoon trough. The result is typically below-average rainfall through the early wet season (October–December), with conditions closer to average – or occasionally wetter – once the monsoon does eventually arrive later in the season.
However, the 1972–73 record shown above has since been broken. The 2024–25 wet season saw Darwin’s latest monsoon onset on record, arriving on 7 February 2025, more than a week later than the 1972–73 benchmark.
This season was not a strong El Niño year (ENSO was neutral at the time); the Bureau of Meteorology attributed the delay specifically to unfavourable timing of the Madden–Julian Oscillation (MJO), a separate tropical climate driver. It’s a useful reminder that while El Niño reliably pushes the odds toward a later monsoon, it isn’t the only mechanism that can delay it and the current event shouldn’t be assumed to break this record purely because it’s a strong El Niño.
Cyclone activity historically subdued
Tropical cyclone frequency is also strongly linked to ENSO phase, as shown in the table above. El Niño years typically bring below-average cyclone numbers across the Australian region, along with a later first landfalling cyclone, often pushed back from early January into later in the season. Queensland in particular has historically been about half as likely to see a cyclone crossing during El Niño years compared with neutral conditions, though 1972–73 (15 cyclones) is a reminder that El Niño shifts the odds rather than guaranteeing a quiet season.
The image below shows Australian region tropical cyclone totals from 1980 to 2026 against ENSO phase, illustrating how consistently El Niño seasons cluster below the long-term trend line, while La Niña seasons cluster above it.
It also shows a longer-term decline in cyclone numbers overall, at roughly one fewer cyclones every 11 years – worth factoring into long-range infrastructure and risk planning, independent of any single season’s ENSO state.
For operations dependent on cyclone-affected shipping windows, port closures and offshore logistics, a below-average cyclone season can mean fewer weather-related disruptions to loadout schedules. However, it doesn’t remove the risk of an individual high-impact system, and a slow start to the wet season can still be followed by intense, short-duration rainfall once the monsoon does arrive.
Separately, while overall cyclone numbers are trending down, research indicates a shift toward proportionally more intense systems as sea surface temperatures rise—a pattern relevant to peak-event risk even as the total count declines.
Lessons from past strong El Niño events
Beyond monsoon delay, the strongest El Niño events on record consistently carried compounding heat, drought and fire risk. The 1982–83 event produced Australia’s driest 11-month period on record across five states and territories, with the heat and drought conditions contributing to the Ash Wednesday bushfires.
The image below shows rainfall deciles for the 1982-83 wet season (October 1982–April 1983). Widespread red areas across the Top End, Cape York and the eastern seaboard reflect severe drought. But a pocket of above-average to record rainfall through central/interior WA stands out as an exception—a pattern echoed in current 2026-27 spring outlooks, which similarly point to wetter conditions through central and western WA even as the east trends dry.
Image: Wet season rainfall deciles between October 1, 1982, and April 30, 1983. Source: Bureau of meteorology
The 1997–98 event brought Australia’s warmest summer on record at the time, while 2015–16 set a spring temperature record for southern Australia that still stands today.
The current event’s early development most closely resembles 1997–98 and 1902-03, suggesting operators should plan for a similarly delayed, drier-than-average build-up to the wet season and above-average heat through spring and summer.
For operators, this heat signal has direct workforce implications. The pre-monsoon build-up – which is typically the hottest, most humid stretch of the year in the north—already carries elevated heat-stress risk for outdoor and FIFO workers. A strong El Niño extends and intensifies that window, with above-average temperatures more likely to persist into and through summer rather than easing early. Reviewing heat management plans, hydration and work/rest protocols, and rostering flexibility for extreme-heat days ahead of the build-up is worth prioritising this season.
What does this mean for operators in Mining and Resources?
With El Niño already in rare territory for this time of year, and unlikely to peak until closer to summer, mining and resources operators in the north should factor the following into wet season planning:
- Extended dry-season conditions into October and November, with implications for dust management, water allocation and bushfire risk around inland and southern operations.
- A likely delayed monsoon onset, pushing the bulk of wet season rainfall and the associated haul road, tailings and access disruptions later into the season, potentially into January.
- A historically below-average cyclone season, which may reduce weather-related shipping and port disruptions, though isolated intense systems remain possible.
- Elevated heat risk during the pre-monsoon build-up, a period historically associated with some of the highest workforce heat-stress risk of the year.
As with any seasonal outlook, El Niño doesn’t act in isolation – the Indian Ocean Dipole, the Southern Annular Mode, the Madden Julian Oscillation and sea surface temperatures around the Australian coast will all influence exactly how this event plays out.
But with the 2026–27 event already tracking as one of the fastest-strengthening on record, operators with exposure to northern Australia’s wet season logistics have good reason to start scenario-planning now.
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