Anyone who just spent the weekend in Sydney knows it was hot. How hot exactly? Well, it turns out there has literally never been a weekend like it.

November 28 and 29, 2020, will go down in history, as the first ever weekend with back-to-back maximum temperature readings of 40 degrees or higher at the city's "official" weather station at Observatory Hill.

On Saturday, temps peaked at 40.8. On Sunday the mercury reached 40.5. As mentioned, this was unheard of. Never before had Sydney experienced consecutive 40 degree days on a weekend.

In fact, Sydney has experienced consecutive days of 40-plus only once before in its history - in January, 1960.

Maximum temperatures on the weekend were even hotter at Sydney Airport, where the mercury reached 43 and 42.6 respectively on Saturday and Sunday.

Image: It was scorching from dawn till dusk. Source: Pixabay.com

Between the two hot days, Sydney residents endured an uncomfortable Saturday night, with an overnight low of 25.3 degrees (9.6 above average) at Observatory Hill, which was the highest November minimum in 162 years of records.

Even coastal locations like Bondi - which can often be around 15 degrees cooler than Sydney's western suburbs - felt the full brunt of the heat on both days.

Bondi hits 40 degrees #heatwave #bondibeach #lifeguardhoppo #sweltering pic.twitter.com/UiBPB2BZIO

— Bruce Hopkins (@lifeguardhoppo) November 28, 2020

So what happened exactly?

"The hottest days at Observatory Hill usually occur when the westerly winds ahead of an approaching southerly change hold out a sea breeze," Weatherzone meteorologist Ben Domensino explained.

"It's unusual for the sea breeze to be held out for two days in a row."

But with unusually persistent northwesterlies streaming down from Queensland, the sea breeze was nullified all weekend. Then at about 5 pm on Sunday, the much-awaited southerly blew in and cooled down the city's temperatures - and the tempers of its residents!

Monday is a grey and relatively cool day in Sydney so far, with maximum temperatures in the low 20s across the city.

The relief could be short-lived for western sydney residents, with temps set to soar into the low 40s on Tuesday, the first day of summer.

But this will be a more typical summer's day in the harbour city, with the cooling sea breeze moderating top temps just below 30 degrees in the CBD and eastern half of the city.