Sydney has just capped its sunniest November since 1990, with the relatively warm and dry conditions set to extend well into the start of summer.

Last month was the city's equal-fourth warmest November for maximum temperatures in records going back to 1858, with average temperatures reaching 26.1 degrees, the Bureau of Meteorology said in its latest report. Sydney Airport had an average of 9.5 hours of sunshine during the month.

"It's been persistently warm, particularly in the east," Acacia Pepler, a climatologist at the bureau, said.

The month had 18 days above 25 degrees, the most since 1894 , and its coldest day was a mild 22.7 degrees. All previous Novembers had at least one day below 21 degrees in the city.