Sydneysiders have endured their hottest summer since records began, with official data revealing records across the city were smashed during the 2016-17 season.

Summer facts Hottest day: 47C at RAAF Base Richmond on February 11, 2017

Hottest day: 47C at RAAF Base Richmond on February 11, 2017 Warmest night: 27.5C in Parramatta North, Springwood and Sydney Airport on December 14, 2016

Warmest night: 27.5C in Parramatta North, Springwood and Sydney Airport on December 14, 2016 Wettest day: 85mm of rain at Sydney Observatory Hill on February 8, 2017

The mercury peaked at 47 degrees Celsius at RAAF Base Richmond on February 11, according to official figures from the Bureau of Meteorology.

But that fell short of Sydney's all-time record of 47.8C set in 1939.

New city average records were also set on February 11 at Badgerys Creek and Penrith Lakes.

Sydney Observatory Hill broke its summer record for all maximum, minimum and mean temperatures, with 11 days of 35C or higher recorded.

Western Sydney notched up a record number of days over 40C, with Richmond racking up 10.

Sydney also sweltered through some hot nights, with 58 nights remaining above 20C and no nights in summer falling below 15C.

The rainfall figures across the city were less impressive with a mostly average 32 days of rain recorded at Observatory Hill.

There were five days that recorded more than 25mm of rain, mostly in early February when flash flooding hit parts of the city.

Across New South Wales it was the third-hottest summer on record, with Walgett reaching 47.9C in February.

Yamba recorded its driest February on record with just 3.6mm of rain falling in the town, breaking a record set more than 90 years ago.