Sydney reached 30°C just before 2pm this Friday, and edged up to 30.3°C at 2:30pm, making it just the third time the city has reached the 30-degree mark in winter since records began in 1858.

Sydney's August (and winter) record is 31.3°C, and while Friday's maximum appears to have fallen short of that mark, other parts of the city recorded their hottest winter day on record.

Sydney Airport broke its winter record of 31.1°C this Friday, reaching 31.6°C at 2:48pm.

Even though the main city weather station's record hasn't been broken, this week's heat has still been remarkable because of its persistence. Bear in mind that the average winter maximums at Sydney’s main weather station at Observatory Hill (on the fringe of the CBD near the Harbour Bridge) are:

• June 17°C
• July 16.5°C
• August 17.9°C

CLICK HERE FOR LONG-TERM SYDNEY CLIMATE DATA

In August 2024 to date, Sydney's running average maximum has been 21°C, some 3.1 above the long-term average.

Sydney maximum temps over the last 10 days up until and including Friday have been:

• 26.2°C, 23.7°C, 22.9°C, 26.9°C, 23.1°C, 24.9°C, 23.5°C, 28.1°C, 24.5°C, 30.1°C

So that's an ongoing stretch of 10 days when each day's maximum temperature has been at least five degrees warmer than average, with some days well over 10 degrees above the average.

By any measure, that is a remarkable run.

The unseasonable heat is being caused by exceptionally warm northwesterly winds for winter. These winds are being driven over eastern Australia by a strong low pressure system far down in the Southern Ocean, and an associated cold front flicking southern Victoria and Tasmania.

While the front is causing bitterly cold weather in Tasmania, most of the cold air staying is well south of the mainland.