Australia is heading towards its hottest December ever as temperature records have already been broken at the start of the country’s summer.

Health warnings and fire bans were issued by authorities as the mercury rose across the nation.

South Australia has been put on alert for “catastrophic” fire danger amid concerns about massive bushfires sweeping across the incredibly dry region.

The town of Marble Bar, thought to be the country’s hottest on average, in the nation’s northwest broke its record for all-time highest temperature on Thursday, reaching 49.3C.

Meteorologists said records will be sent “tumbling” as the capital, Canberra, joins a list of places bracing for their hottest December days on record over the weekend.

Big cities like Sydney, Melbourne and Adelaide are set to record monthly average temperatures up to 16C higher than usual.

“We’re going to see December records tumbling,” said Diana Eadie, a meteorologist at the Bureau of Meteorology. “We’re definitely not out of it yet, in fact I would say it’s going to be peaking over more populated areas this weekend.”

December marks the beginning of summer in the southern hemisphere, with January and February often getting much hotter.

The extreme heatwaves are bad news for Australian farmers, who have already suffered devastating droughts in recent months.

Historic sites across UK exposed by heatwave Show all 15 1 /15 Historic sites across UK exposed by heatwave Historic sites across UK exposed by heatwave Crop marks show of the old garden at Gawthorpe Hall, Lancashire Lancashire Council / SWNS.com Historic sites across UK exposed by heatwave Garden at Gawthorpe Hall, Lancashire which was taken out in the 1940's but can now be seen again through the parched grass Lancashire Council / SWNS.com Historic sites across UK exposed by heatwave Remnants of WWII Air raid shelters on Jesus Green in Cambridge show up in the parched grass SWNS.com Historic sites across UK exposed by heatwave Old crop marks in Norfolk show up Mike Page / SWNS.com Historic sites across UK exposed by heatwave Info showing how crop marks are made SWNS.com Historic sites across UK exposed by heatwave Old parts of RAF Lasham's airfield show up in the parched grass in Hampshire Jordan Bridge / SWNS.com Historic sites across UK exposed by heatwave Crop marks near Langstone, Newport RCAHMW / SWNS.com Historic sites across UK exposed by heatwave Crop marks show in Tregaron, Wales RCAHMW/SWNS Historic sites across UK exposed by heatwave Remnants of Caistor Roman town in Norfolk Mike Page / SWNS.com Historic sites across UK exposed by heatwave Penllwyn Roman fort in Ceregigion, Wales RCAHMW / SWNS.com Historic sites across UK exposed by heatwave Crop marks show in Tregaron, Wales RCAHMW / SWNS.com Historic sites across UK exposed by heatwave Old parts of RAF Lasham's airfield Jordan Bridge / SWNS.com Historic sites across UK exposed by heatwave Roman site near Magor, South Wales RCAHMW / SWNS.com Historic sites across UK exposed by heatwave Old crop marks in Norfolk Mike Page / SWNS.com Historic sites across UK exposed by heatwave Cross Oak hill fort in Talybont, Wales RCAHMW / SWNS.com

“It adds insult to injury,” said Laureta Wallace, a spokesperson for the National Farmers’ Federation. “Most farmers would have got some rain prior to Christmas but the benefit of that will have been eroded with this heatwave. Water’s an issue.”

The nation’s Bureau of Meteorology attributed the conditions to a combination of hot air blown from the northwest towards the densely populated southeast, where a “blocking” effect was stopping cooler winds from moving it on.

Heatwaves and associated wildfires have been a global problem over the last year, striking from the Swedish arctic to California.

Britain experienced a hot spell as part of a heatwave that swept across the northern hemisphere, pushing temperatures close to record levels and causing a spike in heat-related deaths.

Wildfires in Greece and the US also turned deadly, with the Camp Fire that struck northern California becoming the most destructive wildfire in the state’s history. As it raged throughout much of November, the blaze destroyed thousands of buildings and claimed the lives of 86 people.

Scientists warned events of this magnitude are likely to become more frequent and intense as global average temperatures increase.

The “fingerprints” of climate change on such events have been measured by researchers, and the UK Met Office concluded the European heatwave was made 30 times more likely due to the human-induced warming.

Support free-thinking journalism and attend Independent events

In light of these warnings, many nations have reaffirmed their pledges to cut greenhouse gas emissions to tackle global warming, but Australia has proved resistant to such changes.

After the United Nations Intergovernmental Panel on Climate Change concluded countries must cut out fossil fuels within decades to avoid catastrophic warming, Australian ministers insisted they would continue using coal.