A similar pattern was true for most of NSW, with a dry, dusty and record heat making way for a wetter, more moderate end to the season.
“It was exceptionally dry – record dry – in December, a bit more mixed in January, and in February we tended to see a bit more rainfall, particularly close to the coast,” Andrew Watkins, a senior climatologist at the Bureau of Meteorology, said.
“It’s looking like we’ll be well above 2 degrees warmer than average for the summer as a whole for NSW.”
For the country as a whole, this summer will likely end up one of the three hottest for daytime temperatures in records going back to 1910. Despite good rain for some areas in February, summer rainfall was below average.
Mr Domensino said while this season may have felt milder than some recent summers, “prior to this season, the country’s three hottest summers on record have all occurred in the last decade – 2012-13, 2017-18 and 2018/19”.
The climate drivers of extremes came mostly from the Indian Ocean and to the south of Australia.
“At the start of summer, we saw both a very strong positive Indian Ocean Dipole and a near-record negative Southern Annular Mode, and that resulted in both the warmest and driest December on record, with significant fire weather throughout many parts of the country,” Dr Watkins said.
The shift towards more neutral conditions and the exceptionally late arrival of the northern monsoon brought tropical moisture to the continent, taking the edge off the centre’s extreme heat.
“The rainfall helped contain many of the long-lived bushfires in the east and helped ease drought conditions in some locations. But many inland regions experienced only patchy rainfall and we still need to see sustained rainfall to relieve drought in many areas,” Dr Watkins said.
Mr Domensino said rainfall varied. While Sydney water storages almost doubled their capacity after the February deluge “more than 98 per cent of NSW is still considered to be in one of three drought categories”.
For the coming autumn, the odds favour average rainfall for NSW and warmer than normal temperatures.
The background warming with climate change means above-average temperatures are very much the norm.
“January 2020 was [NSW’S] 39th consecutive month with an above-average mean temperature and February is likely to be the 40th,” Mr Domensino said. “Put another way, we haven’t seen a cooler-than-average month in NSW since October 2016 based on mean temperatures.”
Peter Hannam writes on environment issues for The Sydney Morning Herald and The Age.