Australia’s 2017 winter was hot and dry with the average maximum temperature up nearly two degrees Celsius above the long-term trend.
The average maximum daily figure across all of the country for June, July and August was 23.7°C, which smashed the previous record of 23.4 set in 2009, reported the Bureau of Meteorology.
It was the hottest winter on record for Western Australia, Queensland and the Northern Territory, while New South Wales and South Australia made the top three.
Australia’s mean temperature for the start of winter was 0.47°C above the 1961–1990 average and ranked among the top-30 warmest Junes in the nation’s 108-year record, according to the National Oceanic and Atmospheric Administration’s (NOAA) global report.
The average maximum temperature was 1.33°C above average and the seventh highest June maximum mark since records began in 1910. Regionally, Queensland had its highest June maximum since 2001 and the ninth hottest recorded, while Western Australia had its third highest June temperature at 1.72°C above average.
Globally, the combined land and ocean surface temperature for June was 0.82°C above the 20th century average of 15.5°C and the third highest June on record, behind 2016 (+0.92°C) and 2015 (+0.89°C).
At sea, the northern Atlantic Ocean had the most notable cool temperature departure from average, with temperatures 0.5°C to 1.0°C below the 1981–2010 average. No land or ocean areas had record cold June temperatures.
Meanwhile, the average global ocean surface temperature during June was 0.70°C above the 20th century average of 16.4°C – the third highest June temperature since global records began in 1880, behind 2016 (+0.78°C) and 2015 (+0.74°C).
In July the global land temperature was 1.20°C above the 20th century average of 14.3°C and the highest July land temperature recorded. This value surpasses the previous record set in 2016 by 0.07°C. The global ocean temperature was third highest on record at 0.69°C above the 20th century average of 16.4°C, behind 2016 (+0.78°C) and 2015 (+0.75°C).
Australia had its highest July mean temperature since 1975 and the third highest in the books, with a mean temperature departure from average of 1.81°C above the 1961–1990 average.
The August 2017 global land and ocean temperature was 0.83°C above the 20th century average of 15.6°C and the third highest August global temperature recorded, behind 2016 (+0.90°C) and 2015 (+0.88°C).
Australia closed out its winter with a mean temperature that was 1.04°C above the 1961–1990 average and the ninth highest August temperature recorded.
Andrew Watkins, manager of extended and long-range forecasts at the Bureau of Meteorology, said the real reason for the warmth was the persistent high pressure seen particularly during early winter.
“But you also have to add to that the long-term warming trend,” he said.
“The higher than average pressure has kept the skies clear and rain away — meaning more heating of the inland from the sun and less evaporative cooling from ample water on the ground.”
The August Antarctic sea ice extent was 17.50 million square km, which was 650,000 square km, or 3.6 percent, below the 1981-2010 average.
This was the second smallest August Southern Hemisphere sea ice extent on record – ice growth nearly stopped for several days at the beginning and end of the month.
Image Credit: https://www.ncdc.noaa.gov/sotc/global