Australia has just finished its fourth-hottest year since records began in 1910. Credit:Peter Rae The Rural Fire Service has declared total fire bans for the Sydney metropolitan region including the Blue Mountains as well as the Central Coast and the Illawarra/Shoalhaven district. Hot, dry north-westerly winds will raise the fire danger rating to "severe". The RFS issued an emergency fire warning on Tuesday afternoon for two fires burning near Cessnock in the Hunter Valley. That warning was later downgraded as fire crews totalling about 70 people gained the upper hand. Water-bombing aircraft, including helicopters, were brought in to quell the flames as they neared homes at Abermain and Neath, and electricity was briefly cut to residents as flames neared powerlines.

After a hot night, many Sydneysiders hit the beach early on Wednesday. Credit:Peter Rae Sydney has had only three previous back-to-back days of 37.8 degrees or warmer weather, the most recent in November 2002, Agata Imielska, senior climatologist at the bureau, said. The other two occasions fell in January - in 1946 and 1960. Workers' productivity might also take a hit on Wednesday because of the exceptionally warm overnight conditions. A warm night and another hot day ahead for Sydney. Credit:John Veage Through the night, the temperature in Sydney remained above 27 degrees. The coolest point came at 6.34am, with 27.1 degrees recorded at Observatory Hill, bureau data shows.

Penrith residents fared better, with the mercury dipping to 21.8 degrees at 5.18am. Sydneysiders hit the beach at Coogee early on Wednesday morning. Credit:Peter Rae The December record-high minimum was 26.3 degrees set on Christmas Day in 1868. With the bureau's data beginning in 1858, only a handful of monthly records are older than the 1868 record. Hayley Brown, with her nephew Kaius, sought some relief from Tuesday's heat at Parramatta Lake. Credit:Ben Rushton

Ms Imielska said she would be "putting up the summer tent" in her backyard in a bid to get some relief. A warming climate means "progressively, these older temperature records are being broken", she said. Not only are hot records falling at a much higher rate than cold-weather ones, the margins by which records are being eclipsed is also tending to widen, she said. Tuesday's heat was widespread. Adelaide, Canberra and Melbourne all joined the Harbour City in topping 33 degrees, the first time that's happened in December since 1965, Weatherzone said. "It's a very hot air mass," Jacob Cronje, a senior meteorologist at Weatherzone, said.

Relief on the way Relief in the form of a cool change should start to arrive by 4pm to 5pm on Wednesday as fresh north-westerly winds start to turn into southerlies. It will take a bit longer, perhaps until 5pm to 6pm, before the "true cooling gets going" for the city, Jordan Notara, a Bureau of Meteorology forecaster, said. Winds could strengthen to 50km/h or more along the coast. Thursday may even feel chilly, with just 22 degrees tipped for the city, before the mercury climbs back to the low 30s by Saturday. Fire crews may have a busy time before cooler conditions arrive.

Warm times For Sydney, Tuesday's top was the city's warmest for December in 11 years. With weak sea breezes, the maximum temperature was similar across the basin. Richmond's top of 39.6 degrees pipped Hornsby and Penrith to be the city's hottest. December days of 35 degrees, or warmer temperatures, occur on average slightly less than once a year. If Wednesday clears that mark, as the bureau predicts, this December will have clocked three such days in the first half of the month alone.

The last time there was such a trio of warm days in a December was in 2000, with the record number of five set in 1979, Acacia Pepler, a bureau climatologist, said. With the lingering heat, the Bureau of Meteorology said the strip of coastal NSW will have a low-intensity heatwave for Tuesday to Thursday. (See chart below.) Other districts with total fire bans on Wednesday are the state's upper central and lower central west plains regions. Help for homeless

The City of Sydney, meanwhile, stepped up efforts to help people sleeping rough during the hot spell. It is working with NSW Family and Community Services and St Vincent's Homeless Health Services to ensure homeless people have access to water, temporary accommodation, health services, sunscreen and shade. "City staff and specialist homelessness services are on patrol in the city, providing advice and support to rough sleepers," the city said. "The city's community centres and libraries will also be open, providing a safe and comfortable space to escape the heat," the city said, adding that those with medical emergencies should ring triple zero. With Georgina Mitchell, Kate Aubusson Loading

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