Spring scorcher to follow record warm winter for south-east capitals

Australia has just finished one of the hottest winters ever recorded, and the heat is not stopping there. Cities like Sydney and Melbourne saw their warmest winters since weather records began in the 1850s. Now, forecasters say spring is likely to break even more records across the country.

Canberra also had its hottest winter on record, while Adelaide and Hobart ranked second-warmest ever. Temperatures were so far above normal along the eastern coast that the weather felt more like cities much farther north. For example, Sydney's average winter temperature was 15.3 degrees Celsius — that is 2.3 degrees above the long-term average, and only a tiny bit below what Brisbane normally feels like in winter.

The shift was noticeable in other cities too. Hobart's average winter temperature of 10.4°C matched Melbourne's usual winter average. Meanwhile, Melbourne's 12.2°C was just 0.8 degrees below Sydney's historic winter norm. It was as if the climate zones of Australia had slid southward by hundreds of kilometres.

One of the clearest signs of the unusual winter was the lack of cold days and snow. Brisbane only had two days where the temperature stayed below 20°C. Canberra had just one day below 10°C, and its coldest day of the whole winter reached 9.5°C on July 13 — that was 3°C warmer than a typical coldest day there.

Sydney also set a record for its mildest cold day of winter. The lowest daytime high in Sydney this winter was 15.5°C on June 25, beating the old record of 14.6°C set in 1979. Because there were few bursts of polar air pushing north, snow was very rare across the mountains. Snow did not fall in the Blue Mountains west of Sydney for the fourth year in a row — something nearly unheard of last century.

Perth, on the west coast, had a much more ordinary winter. Its temperatures were only 0.3°C above the long-term average, making it cooler than the eastern states. This shows that the unusual warmth was mainly concentrated on the eastern side of the country.

Scientists say the extreme heat comes from a mix of causes. Natural weather patterns, long-term climate change, and a strong El Niño event are all playing a role. El Niño is a natural warming of ocean temperatures in the Pacific that can push heat across Australia, and there have also been very few cold fronts arriving from the Southern Ocean to cool things down.

Spring is expected to start with a burst of warm north-westerly winds across south-eastern states. Canberra is predicted to hit 21°C on the first day of spring, and both Melbourne and Adelaide could reach 22°C. That would make it the warmest September 1 in five years for all three cities. Sydney could see 25°C to 27°C, while Brisbane may reach 31°C by that first week — about 7°C above normal.

Weather models are predicting that southern Australia will experience its warmest spring on record over the next three months. The Bureau of Meteorology's ACCESS-S model shows most of the south could see temperatures 2°C to 3°C above recent averages. When compared to pre-industrial levels, that gap rises to between 3°C and 4°C — a very large shift when spread across an entire season.

The BOM's models also show there is more than an 80 per cent chance southern Australia will record maximum temperatures in the top 20 per cent of all years on record. The same high probability applies to overnight low temperatures, covering about two-thirds of the country. Even forecasts for early summer show no sign of relief, with most of Australia predicted to run 1°C to 2°C above average in January.