Bendigo used to experience fewer than one January day of above 40 degrees on average before 1991, but has sweated through five so far just 18 days into the month.
Senior climatologist Blair Trewin said the heatwave is part of a Australia-wide trend towards more and more hot days each year, part of a worldwide warming pattern.
Only 0.4 days each January – or two days in five years – exceeded 40 degrees between 1957 and 1992.
Between 1991 and 2018 an average of 1.4 days each year exceeded 40 degrees each January.
Five days have soared above 40 so far in 2019, just over halfway through January.
And that’s just the ones recorded. The Bureau of Meterology’s weather station automatic weather station took no measurements for two weeks between December 21 and January 3, due to an electric fault.
According to Dr Trewin heatwaves are becoming more frequent in Bendigo, as with the rest of Australia.
Bendigo had never experienced three days in a row above 40 degrees before the 2009 heatwave a week before Black Saturday.
That year Bendigo sweated through five days in a row over 40 between January 28 and February 1.
Two separate heatwaves with four days in a row above 40 hit Bendigo in 2014.
“Particularly in inland south east Australia we’ve seen a sharp increase in the number of hot days,” Dr Trewin said.
“We see a substantial long term warming trend through Australia as we do globally.
“Australia has warmed by over a degree since 1910. With higher average temperatures you’d expect to see more heat extremes and that’s what we are seeing.”
The current heatwave is due both to the failure of a monsoon to develop over northern Australia, a lack of high pressure systems in the Tasman Sea and the start of a weak El Niño.
It’s not the temperatures that are interesting about the current heatwave.
“The most exceptional thing about this is that it’s affected such a large area of Australia, more so than how extreme it’s been in any particular place,” Dr Trewin said.
Having experienced several sets of hot days in January doesn’t make Bendigo likely to be any cooler during February.
Conditions are likely to cool by Friday over Victoria, but are forecast to heat up again next week.
Dr Trewin said that continuing hot conditions in central Australia mean that Bendigo is slightly more likely to experience a heatwave during February.
Bendigo is also looking set to exceed the mean maximum temperature for January by more than five degrees.
To date the mean maximum temperature is 35.1 degrees, while the average is 30.
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