After the wettest start to a year in two decades, Sydney has now endured its driest three months in a decade, according to weatherzone.com.au.
The driest October in five years has helped the past three months become the driest since 2002, Weatherzone meteorologist Brett Dutschke said.
The past three months have delivered only 72 millimetres of rain, well short of the 227mm average for August to October.
The last time there were three consecutive months drier than the last three was September to November 2002, when there was only 59mm.
There have only been 10 drier three-month spells in more than 150 years of records.
It has been a remarkable turnaround, given that Sydney had its wettest first six months of a year since 1990. The January-to-June total was 988mm, well above the 728mm average.
"The atmosphere has dried out quite a bit in the last few months since La Nina ended," Mr Dutschke said.
"Oceans surrounding Australia have cooled down more than normal in this time, reducing the moisture in the atmosphere and the potential for big rain. Also, most cold fronts have originated too far west and have lost moisture by the time they reached Sydney.
"Cloud cover was down about 15 per cent compared to average. This equates to an extra one-and-a-half hours of sunshine per day, which allowed the average daytime temperature to be almost two degrees warmer than normal," he said.
"It's been great for most outdoor activities but gardens and parks have become dustier and the pollen count has been up, making life a bit uncomfortable for allergy sufferers."
October ended up being the warmest in five years, regarding daytime temperatures. The average maximum was 23.2 degrees, one above the monthly long-term norm.
Clearer skies meant that Sydney had its coolest October nights in nine years, averaging an overnight minimum of 13.8 degrees.
October was the wetter of the last three months with 29mm but this was still well short of the 77mm average and the driest since 2007.
"Looking ahead to the next few months, warming oceans should allow rainfall to trend to near-average with help from a near-neutral phase of the ENSO system [neither strong El Nino nor strong La Nina]. Daytime and overnight temperatures should turn out to be near or just above average," Mr Dutschke said.
Sydney weather statistics can be seen here.
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