Phew! After Hottest Day Of The Year, Sydneysiders Celebrate the Southerly

"It's here! We can live again."

The southerly is in. We repeat: the southerly is in.

It was hot across the whole of Sydney this Thursday afternoon -- especially in the CBD and eastern suburbs, which are usually spared the worst of the city's heat.

But the southerly is now in, and temperatures have dropped around 15 degrees within a few minutes.

Earlier today, temperatures rapidly approached 40 at the city's official measuring station at Observatory Hill, right beside the Harbour Bridge. At 3: 30 pm, the mercury hit 39.2. At 4:30 it was 39.3.

This was easily Sydney's hottest day of the year and naturally, locals were melting like ice cream on a BBQ.

Power went for a while in the eastern suburbs this morning due to an underground cable fault and, yeah, not great timing.

This was all quite unusual for poor old Sydney, where the average January maximum temperature at Observatory Hill is a surprisingly mild 26 degrees.

Usually, the Sydney CBD and eastern suburbs are significantly cooler than the city's western suburbs, due to the moderating effect of sea breezes.

For example, several suburbs in the city's west have topped 40 so far this year on at least four days. By comparison, the CBD has hit 35 just twice, with a high reading of 37.8 on January 5.

It really is a mild micro-climate in the city's east. But not today. As you can see in the Bureau of Meteorology's 4 pm MetEye graphic below, it was hot everywhere in Sydney today.

This was all happening because of a strong push of hot dry air from the north-west. That airmass was so strong, it kept sea breezes well out to sea for much of the day.

But by mid afternoon, the Bureau promised a so-called southerly buster was on its way.

And despite the strong and possibly damaging winds that accompany a strong southerly change, the whole city was eagerly awaiting it.

To celebrate the tempreature drop, we've embedded a lovely video of America's current cold snap at the top of this story.