Ocean 2-3°C above average off the east coast

The east coast sea is unusually warm for winter

While the southern states shiver through a run of cold fronts, the sea along the east coast is doing something unusual for the middle of winter.

The Bureau of Meteorology's sea surface temperature analysis for the week ending 26 July shows waters off New South Wales and eastern Tasmania well above average.

Across large patches the anomaly reaches two to three degrees, a big margin for the open ocean, where temperatures usually shift slowly.

The Bureau expects the warmth to continue in the months ahead, so this is a pattern to plan around rather than a passing blip.

What the numbers show

Sea surface temperature is simply how warm the top layer of the ocean is, and it changes far more slowly than the air above it.

A two to three degree anomaly may sound small, but it takes an enormous and sustained input of heat to lift that much water that far.

The warmest patches sit along the New South Wales coast and reach down to eastern Tasmania, one of the fastest warming stretches of sea on the planet.

Because the ocean holds heat so well, an anomaly this size tends to linger for weeks or months rather than fading in a few days.

What is driving it

Three ingredients are stacking on top of each other, and each one on its own would nudge coastal waters warmer.

The first is the East Australian Current, the warm southward flow that carries tropical water down the coast and spins off warm eddies as it goes.

The second is an active El Nino, with the Bureau's key Nino3.4 index sitting near two degrees above average, far beyond the El Nino threshold.

The third is the background heat in the global ocean, with June 2026 ranking as one of the warmest on record for worldwide sea temperatures.

Layer those together and the unusually warm water off the east coast starts to look less like a fluke and more like the sum of its parts.

"Two or three degrees is a lot for the open ocean; the sea does not warm like a bathtub, so this kind of anomaly tells a real story."

What it means for fishers

The most obvious effect is on the fishing, because warm water carries warm-water species further south than they would normally venture.

Pelagic fish such as marlin, mahi mahi and wahoo follow the warm eddies down the coast, and kingfish hold hard around headlands and structure.

Summer species that would normally have moved on can linger later into the season, so the calendar you fished last year may not apply.

The flip side is that cooler-water fish may sit deeper or further offshore, chasing the temperatures they prefer away from the warm surface layer.

If you are chasing pelagics, remember the New South Wales size and bag limits still apply, including a 65 centimetre minimum on yellowtail kingfish.

Divers, swimmers and surfers

For divers and swimmers the warmth means more comfortable water and, often, a richer parade of tropical visitors carried south on the current.

The trade off is that warmer water can bring more stingers, including bluebottles, so it pays to check conditions and heed any beach signage.

Surfers are unaffected in the water itself, but the same big systems driving southern swell still reach the east coast points and beaches.

Whatever your sport, warm surface water does not mean the danger has gone, and rips and sets behave the same regardless of temperature.

The cost beneath the surface

The warmth that helps the fishing also puts real pressure on habitats built for cooler conditions, especially the further south you go.

Eastern Tasmania has warmed faster than almost anywhere else in the ocean, and its giant kelp forests have thinned dramatically over recent decades.

Prolonged warm spells stress kelp, shift the range of species like the long spined sea urchin south, and reshape whole underwater communities.

So the same anomaly that lights up the fishing off Sydney is a warning sign for the temperate reefs off the Tasmanian coast.

How long will it last

The Bureau's outlook has above average sea surface temperatures continuing off much of the coast through the coming months.

El Nino events tend to run their course over a season or more, so the ocean is unlikely to shed this heat quickly.

That means the shifts in fishing, the tropical strays and the pressure on cool-water reefs are all likely to stick around for a while yet.

For anyone who spends time on the east coast water, it is worth treating this as the new normal for the season, not a short lived quirk.

Common questions

How warm is the water compared with normal?

The Bureau's analysis for the week ending 26 July shows patches off New South Wales and eastern Tasmania sitting two to three degrees above average.

Why is the east coast so warm when the south is so cold?

The cold fronts hitting the south are weather in the air, while the ocean warmth is a slower, deeper signal driven by currents and El Nino.

Will this change what I catch?

Very likely, as warm-water pelagics push south and linger later, while cooler-water species may move deeper or further offshore to find their preferred range.

Is this good news or bad news?

It is both, lifting the pelagic fishing along the coast while stressing the cooler-water reefs and kelp forests off the southern end.

Keep an eye on conditions with the Seabreeze Sydney wind forecast , and check the local New South Wales tide times before you head out.