14/12/2016 8:23 AM AEDT | Updated 14/12/2016 8:43 AM AEDT

Weather Records Tumble On Sydney's Hot, Sweaty Sleepless Night

Steve Allen
NO WE'RE NOT FEELING GRUMPY TODAY, said absolutely nobody in Sydney.

Don't argue with anybody from Sydney today. Or anyone from Canberra. They will be grumpier than you and they will win. And the reason they'll be grumpy is both cities just sweated through their hottest December nights ever. Ugh.

Some Sydney stats:

  • Sydney's minimum of 27.4 degrees around 6am eclipsed the previous record of 26.3.
  • The MINIMUM temperature overnight was two degrees hotter than the mean December MAXIMUM of 25.2.
  • Sydney was hotter than Darwin last night. That almost never happens.

Canberra also had an oven of an evening. Some stats:

  • Canberra's overnight minimum was 24.2 This was also a record. The old mark was 23.9.
  • As recently as November, the nation's capital had a night where temperatures fell to -1.3. Yep, a subzero night in November.

So what's going on?

The hot spell is all due to an area of superheated, dry inland air which is pushing its way across Australia's south-east.

Sydney in particular is at the epicentre of the hot stuff. It reached 38 in Sydney in virtually all suburbs yesterday, before the sea breeze kicked in and cooled off the coastal areas. A top of 38 is on the cards again for Wednesday, and possibly hotter. At 8am, it was already 30.

Meanwhile, Melbourne will struggle to reach 20 on Wednesday. Why? The weather chart below explains all. If you roughly know where Sydney is on the map, and if you follow the lines going anti-clockwise around the big High (H), you can see that the airflow reaching Sydney comes from the Qld outback. Hot.

But the southerly change has already reached Melbourne. Aaaahhhh. It'll hit Sydney much later tonight, but not before everyone has gotten a lot lot grumpier and sweatier.

Bureau of Meteorology

So is this a climate change thing?

You should never ever take one weather event as evidence of a trend. However, the Bureau's State of the Climate report, released in this year, said that "The duration, frequency and intensity of extreme heat events have increased across large parts of Australia".

This week's hot spell is a low-scale heat event, and barely meets the Bureau's own criteria for a heatwave, which is three straight days of well above normal temperatures. The fact records are being broken in such a minor extreme heat event is, shall we say, interesting.