Sydney sees minimum temperature stay above 27C, the first time the city has witnessed that since 1868.
Chile’s capital Santiago has just broken a 100-year-old old record.
On Wednesday, the city witnessed a maximum temperature of 37.3C, a record not just for December but for any month in Santiago.
Chile’s meteorological service has called this heat “extreme”, and the health ministry has advised people to wear light clothing, drink plenty of water and avoid outdoor activities.
The nation’s forest service, which is currently fighting dozens of forest fires in central Chile, warned of “extreme risk” from fire-ready dry vegetation.
Authorities said that exposure to ultraviolet light – the cause of summer tans and sunburns – was also a concern. Chile is often underneath the “ozone hole” in spring and early summer, but this year, stratospheric ozone – the good sort – has filled in the hole.
Chile is not alone in having a hot spell.
Temperatures are high across parts of central Argentina. Buenos Aires’ average temperature for December is 27C and that has been recorded only twice this month.
Eight days of December have seen temperature above 30C and on Tuesday, it was 35C.
The wind is swinging around to the south as an Antarctic cold front runs up the continent. The forecast for Santiago returns the temperature to about 30C as a result.