Explained: Why coldest ever start to summer wasn’t a record breaker

Despite Brisbane recording its coldest first day of summer in more than 130 years, an official record won’t be recorded because of a rule change.

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December 1, 2022, could have been the coolest start to summer in more than 130 years, but a quirk in the Bureau of Meteorology’s data collection means no official record was broken.

The temperature in Brisbane reached 17.8C just after midday on Thursday, lower than the record for the coldest December 1 which has sat at 18.9C since 1888.

But a warm morning on Friday scuppered this year’s chance at toppling the long-standing record, meteorologist Pieter Claassen explained.

Persistent rain and temperatures as low as 15 degrees had people in Brisbane bring out the brollies with the first day of summer resembling more of a winter feel. Picture: NCA NewsWire/Tertius Pickard

“The way they used to make records was look at the thermometer once a day at 9am, and there’d be a line that marked the highest temperature and a line that marked the lowest temperature since last time, and that’s what would get noted down,” Mr Claassen said.

“We still have to measure 9am to 9am that way so we can compare records, and this morning has already climbed a few degrees higher, so we can’t say any official records were broken.

“There could have been a day 100 years ago that was 15C and the same thing happened where the next morning was warm - we don’t know.”

Some weather stations in the region began collecting temperatures at 6pm two decades ago, meaning it can be confirmed that Thursday was the coolest start to summer in at least 23 years for both Brisbane and the Gold Coast.

Temperatures are expected to increase over coming days, reaching a high of 35C on Wednesday.

The chance of showers continues through the weekend, easing by Tuesday.

Meanwhile, Sky News Meteorologist Rob Sharpe said Queensland’s next three summer months would be wetter than usual and carry an increased tropical cyclone risk due to the La Niña effects.

“All forecast models point towards a more active than usual tropical cyclone season, a greater threat of tropical cyclones making landfall and hitting further down the coast,” he said.

“The reasons behind this are partly because of La Niña … but we’re also seeing record warm seas in the Coral Sea - almost the entire Coral Sea is warmer than usual for this time of year.

“It is very early for us to be seeing this widespread warmth through the Coral Sea, so the warmer seas are there, the weather patterns are conducive, so now it’s a waiting game.”

Originally published as Explained: Why coldest ever start to summer wasn’t a record breaker