An unusually intense early-season heatwave is breaking wintertime heat records in southern Australia, including the highest temperature ever observed near the nation’s south coast in winter.

Plenty of clear sky and a lack of strong cold fronts have allowed unusually hot late-winter air to build up over Western Australia during the last few weeks.

This pool of abnormal winter warmth has caused temperature to rise as much as 15ºC above average over the last few days, with some places setting new records for winter.

On Saturday, WA’s Kalgoorlie reached 32.0ºC, which was its equal highest winter temperature in records dating back to 1907. The following day reached 31.7ºC, making this Kalgoorlie’s hottest pair of winter days on record.

Temperatures then rose even higher on Sunday and Monday as hot air from the WA Interior moved towards the state’s south coast. Some of the standout observations from Sunday and Monday included:

• 35.4ºC at Eyre on Sunday, 15ºC above the August average and its highest winter temperature on record
• 34.4ºC at Eucla on Monday, 15ºC above the August average and its highest winter temperature on record
• 34.4ºC at Red Rocks Point on Sunday
• 31.3ºC at Southern Cross Airport, 13ºC above average and its highest winter temperature on record

Images: Modelled surface air temperature anomalies on Sunday (top) and Monday (bottom), showing temperatures reaching 10 to 15ºC above average near the south coast of WA. Source: tropicaltidbits.com

Incredibly, Eyre’s 35.4ºC on Sunday was the highest temperature ever recorded near the south coast of Australia during winter. The two 34.4ºC observations at Eucla and Red Rocks Point were also the equal third highest south coast winter temperatures on record in Australia.

The hot air will spread further east on Tuesday and send temperatures soaring more than 10ºC above average in parts of SA. This may challenge some winter temperature records in the state’s northwest, where maximums are forecast to reach around 33ºC on Tuesday afternoon.

Australia’s highest winter temperature on record was 41.2ºC at West Roebuck, WA in 2020.