Penrith's top of 47.3 degrees was more than just a local record, and the hot weather is set to stick around.

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A tanker carrying Iranian oil was ablaze in the East China Sea on Sunday after colliding with a cargo ship.

In the end, it didn't quite break the record for Sydney's hottest day, but that was hardly cool comfort for Penrith residents who sweltered through 47.3-degree temperatures on Sunday.

Sydney sweltered on Sunday as the mercury reached over 47 degrees in Penrith. See how your suburb compared.

Emergency services and government agencies are urging people to look after themselves this weekend as a heatwave descends over the state.

When it comes to hype, there is probably nobody as outlandish as US-based billionaire Elon Musk and his Tesla corporation.

When temperatures fall somewhere between 4 and -1 degree Celsius in one of America warmest states, people from West Palm Beach to Miami look out for reptiles.

Much of south-east Australia will roast over the weekend, lifting fire risks to "catastrophic" in parts of South Australia, and sending the mercury in western Sydney to levels more akin to the Outback.

In some parts of the city, temperatures will be in the mid-40s until Monday.

The frequency of severe coral bleaching events has increased fivefold in four decades because of climate change, a pace already exceeding the time needed for some species to recover, a new global study has found.

A powerful winter storm churning up the US East Coast has brought snowfall and gusting winds to a wide swath of the country as forecasters issued dire warnings for the millions of people in its path.

Confusion surrounds the unknown identity of a new species of bird

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Rip currents are already claiming lives this summer, but many of us don't know how to recognise them.

A combination of astronomy and meteorology is bringing tidal floods to low-lying regions.

The Victorian government has signed a "support agreement" for a 20-megawatt battery for the Bulgana Green Power Hub.

The woman was being taken to hospital with a puncture wound and possible fractured arm.

Only 30 per cent of Australians can correctly identify a rip, and about two out of three of those who say they can, cannot do so correctly.

The camping equipment left behind filled four cars, one ute, a van and three trailers.

Brush turkeys are steadily moving out of the forests and into Sydney suburbs, with experts saying we will see an increase in urban areas.

One of Victoria's most-feared marine pests surfaces again in Wilsons Promontory, sparking a desperate push to eradicate it.

A record summer in Sydney and a series of early-season heatwaves helped make 2017 the city's thirstiest year since 2004, Sydney Water said.

Exposure to fine particulates from burning coal, vehicle exhausts and other pollution sources is linked to an increased risk of pre-term births, according to a study of more than 1 million Chinese births that included an Australian researcher.

The hottest day in 12 months is forecast for this Saturday.

A looming heatwave in early 2018 is unlikely to augur an exceptionally hot year for Australia as a weak La Nina in the Pacific will start to tilt the odds to relatively cool and wet conditions for much of the nation.

Sydney's Observatory Hill has witnessed a few storms over the years, and not all of them were meteorological.

Australia is set to round out one of its hottest years on record, leaving fire authorities pinning their hopes a La Nina in the Pacific will bring soaking rains before more heatwaves build through the summer.

Despite Donald Trump's dismissal of the Paris accord, action to address worsening climate threats has gathered pace globally.

• Katherine O'Chee

The Bureau of Meteorology expects Sydney to be "cool and cloudy" on Christmas Day.

Vietnamese media are reporting the typhoon has been downgraded tropical depression and failed to make landfall in the country on Tuesday.