It's beginning to feel like an endless summer for Sydney.
A large high-pressure ridge is sitting over NSW and will drift slowly eastwards, setting the city up for more days of mostly sunny conditions with light winds, Tristan Meyers, a meteorologist with Weatherzone, said.
Sydney's top of 26.2 degrees was almost seven degrees above the May average of 19.5 degrees.
The above-average conditions should extend until the middle of next week at least, and each day until Monday is expected to reach 24 degrees or warmer.
"It's definitely unusually warm for this time of year, particularly in the evenings," Mr Meyers said.
The latest warm start to a month means it's likely May will extend the run of above-average monthly temperatures now well into a fifth year for the city.
Last month was Sydney's equal-warmest April for minimum temperatures and equal second-warmest for mean temperatures.
Sydney has clocked up 118 days in a row of days reaching at least 20 degrees, with only January 6th's 18.6 degree ruining the perfect scorecard in 2016.
The city, though, would need a remarkably mild winter to break the longest run of such days.
The record 20 degree-plus tally is 180 days, which took in the summer of 1913-14. 1990-91 was not far behind with the second-longest streak of 178 such days, Blair Trewin, senior climatologist with the Bureau of Meteorology, said.
Several sites around Sydney have had their warmest starts to any May, including Bankstown - which has 47 years of records - and Prospect Reservoir with 50 years of data, said Agata Imielska, also a senior bureau climatologist.
Rain-wise, Sydney will also remain mostly dry for the current forecast period, with just a few millimetres tipped for late on Sunday and Monday morning, the bureau said.
However, there's a "pretty good chance for substantial rain" over those two days for regions west of the ranges, Mr Meyers said.
Strong winds may also feature across parts of south-eastern Australia over the weekend and early next week, bureau forecast maps indicate.
