The first month of winter 2026 was exceptionally warm for eastern Australia, with Sydney registering its warmest June in records dating back to 1859.

The mean temperature at Sydney’s Observatory Hill weather station during June – calculated by combining daily minimum and maximum temperatures throughout the month – was 16.07°C. This was 2.9°C above the long-term average and the city’s warmest June on record, beating 15.66°C from 1991.

June’s abnormal warmth was felt broadly across Australia's eastern states. When combining temperatures across Queensland, New South Wales, the Australian Capital Territory, Victoria and Tasmania, the mean temperature during June was 16.17°C. This was 2.17°C above the 1961-1990 average and the second warmest start to winter in records dating back to 1910. The only warmer June was 1996, which had a mean temperature anomaly of +2.26°C.

Melbourne, Brisbane and Canberra all had one of their top five warmest Junes on record in 2026.

Why was June so warm?

Temperatures ran well above average in June due to a lack of strong cold fronts sweeping over Australia. This absence of early-winter fronts was associated with a prolonged and strong positive Southern Annular Mode (SAM) event, which saw high pressure systems become a dominant synoptic feature over the Australian region, shielding the country from cold air masses. These highs also promoted more humid easterly wind over eastern Australia, which helped increase overnight minimum temperatures.

In addition to the positive SAM, eastern Australia was also flanked by above average sea surface temperatures in the Tasman and Coral Seas during June. This warm water helped insulate the country’s eastern states and keep air temperatures higher than normal. At times, sea surface temperatures were more than 3°C above average in parts of the Tasman Sea.

Image: Sea surface temperature anomalies in the Tasman Sea on June 29, 2026. Source: Bureau of Meteorology.

The background influence of climate change also played a role in June’s abnormal warmth. Eastern Australia’s mean temperature in June has increased by around 1.5°C since 1910.

Where were the warmest and coldest places in Australia during June?

The first month of winter 2026 featured a mix of temperature extremes across the country. The coldest place in Australia during June was -9.5°C at Liawenee in Tasmania on June 26. The warmest place was 34.9°C at Yampi Sound, WA on June 3.

Here are the highest and lowest in each state and territory during June 2026:

Hottest

NSW/ACT: 27°C at Mungindi

VIC: 23.4°C at Lakes Entrance

QLD: 34.5°C at Weipa

SA: 31.9°C at Oodnadatta

WA: 34.9°C at Yampi Sound

NT: 34.8°C at Bradshaw

TAS: 20.8°C at Campania

Coldest

NSW/ACT: -8.3°C at Perisher Valley

VIC: -4.5°C at Mount Hotham Airport

QLD: -2.8°C at Injune

SA: -1.8°C at Yunta

WA: -2.0°C at Norseman

NT: -0.3°C at Alice Springs

TAS: -9.5°C at Liawenee