Strong El Niño Developing: Dry Months Ahead for NSW and ACT

A significant El Niño weather pattern is developing rapidly in the equatorial Pacific, and forecasters are warning it could deliver a prolonged stretch of dry, hot conditions across New South Wales and the ACT through the remainder of 2026.

As of mid-May, sea surface temperatures in the critical Niño 3.4 monitoring region are sitting just 0.3 of a degree below the official El Niño threshold — after warming by a full degree over the past six weeks alone. Bureau of Meteorology modelling suggests that threshold will be crossed within roughly four weeks, with the system then expected to intensify considerably before being declared a full El Niño event.

What's particularly striking is the strength being projected. The majority of global climate models — not just those from the BOM — are forecasting the event to exceed plus two degrees above the baseline, placing it firmly in the "very strong" category. While some media outlets have rushed to label it a super El Niño, meteorologists are cautioning against that framing, noting it is a non-scientific term that can overstate certainty about regional impacts. What is clear, however, is that a stronger event raises the probability of meaningful impacts — and with large parts of inland New South Wales already in drought, the timing is a serious concern.

El Niño typically brings drier and hotter than normal conditions to eastern Australia, the opposite of the wetter La Niña pattern that brought widespread flooding in recent years. BOM's three-month rainfall outlook for the coming period shows broad swathes of NSW shaded in brown, indicating rainfall is likely to fall in the lowest historical percentile — between 60 and 100 percent below average for many regions. The Hunter Valley, already notably dry, and the northern inland areas including the northwest slopes and plains and northern tablelands are flagged as especially vulnerable. Southern Queensland faces a similarly bleak outlook.

Coastal communities, however, are experiencing a different short-term picture. Above-average sea surface temperatures near the NSW coast, combined with a large, slow-moving high pressure system sitting over the Tasman Sea, are driving strong south-easterly winds onshore. Those winds are picking up moisture from the warmer-than-usual water and generating scattered coastal showers — slightly more than would be typical for mid-autumn. If an East Coast Low were to develop offshore under these conditions, the warm ocean temperatures could act to intensify it beyond what might otherwise be expected.

As a result, temperatures across NSW have been running around two to three degrees above average so far this month, with both daytime highs and overnight lows elevated. The coastal belt is likely to continue seeing cloudy periods and occasional showers in the near term, while inland regions receive little to no meaningful rainfall.

The El Niño is expected to persist for roughly six to nine months, effectively covering the rest of the year. Authorities and landholders in already-dry inland zones are being urged to monitor BOM's rolling seasonal forecasts closely. Below-average rainfall does not mean zero rainfall, but the odds are stacked toward a drier than normal pattern, and the margins in drought-affected areas are already thin.