Key Takeaways:
- Extreme variability in weather conditions across Australia, with hot temperatures in Western Australia and cold temperatures in the south-east
- Perth experiences its hottest start to summer on record, with temperatures reaching 39 degrees Celsius
- Cold snap in the south-east brings snow to alpine regions and record-low temperatures to several locations
- Bushfires in Western Australia pose a threat to homes and communities
- Weather conditions are expected to be short-lived, with temperatures returning to average by the end of the week
Introduction to Extreme Weather Conditions
Summer has begun with extreme variability across Australia, with Western Australia experiencing widespread hot conditions and the south-east of the country facing extreme cold. The contrasting weather patterns have brought record-breaking temperatures to several states, with Perth reaching its hottest start to summer on record and dozens of locations in the south-east experiencing their coldest start to summer in decades.
Record-Breaking Temperatures in Western Australia
In Western Australia, the heat has been intense, with Perth’s temperatures soaring to 39 degrees Celsius on Monday, marking the city’s hottest start to summer on record. The city was one of dozens of places in the state’s west and south coast feeling the heat, with emergency-level bushfires currently threatening homes in the mid-west. The regional city of Geraldton, 400 kilometers north of Perth, also experienced its hottest start to December in nearly 100 years, hitting 42.2°C. The extreme heat has brought firefighters to battle a bushfire in the area, with one home lost and hundreds of others under threat.
Cold Snap in the South-East
Meanwhile, a wintry start to the season has had the country’s south-east shivering, with snow falling across the alpine region and temperatures plummeting as much as 15C below average. Dozens of locations across New South Wales, Victoria, and Tasmania are experiencing their coldest start to summer in decades, with strong winds making it feel even more unseasonal. The frigid temperatures are the result of a wave of polar air, which is tracking well north of a typical December path. Several locations are on track to set a record for their coldest start to December, including Thredbo, NSW, which reached a low of -0.8C, and Mount Hotham, VIC, which hit a low of -0.6C.
Impact of Wind-Chill Factor
The wind-chill factor has ensured that the cold weather feels even more bitter, with the "feels like" temperature in Melbourne Airport reaching just 2.5C, despite the actual air temperature being 11.5C. The cold snap has also brought snow to the alpine regions, with the Mt Hotham Alpine Resort Facebook page reporting a low of -0.9C and a dusting of snow. The cold weather has been particularly challenging for Melburnians, who were rugged up on Monday morning as summer got off to a cold start.
Comparison to All-Time Records
While the temperatures in both WA and Vic are notable for the first day of summer, they are a long way off all-time records for December. Melbourne has had temperatures in the low teens on numerous occasions in December in the past, including a record cold December maximum of just 10.4C in 1867. Perth regularly hits temperatures of about 35C during the summer months, with its highest temperature during the month of December being 44.2C on Boxing Day, 2007.
Short-Lived Weather Conditions
Thankfully, both extremes are expected to be short-lived, but the WA heat will track to eastern Australia through the week. A tongue of hot air arriving from northern Australia will track slowly across inland WA on Tuesday and Wednesday, then peak over south-east states from Thursday. For example, in a remarkably variable start to summer, both Adelaide and Melbourne are forecast to reach 33C on Thursday. The sweltering heat in Perth will ease off from tomorrow, bringing relief to residents and firefighters battling the bushfires. As the weather conditions return to average by the end of the week, Australians can expect a more typical summer season to unfold.