Parts of South America have endured an extreme winter heatwave this week, with one town in Bolivia registering the equal highest winter temperature ever recorded in the Southern Hemisphere.

A large blocking high pressure system over the South Atlantic Ocean caused a hot air mass to build over the northern half of South America over the past fortnight.

Earlier this week, this pool of hot air spread into central parts of South America as northerly winds developed ahead of an approaching low pressure trough.

Image: Modelled surface air temperature on August 22, showing temperatures in the mid-40s in Bolivia, and several areas north of the equator. Source: ClimateReanalyzer.org

Image: Same map as above, but instead showing temperature anomalies, which highlight how far above (red) and below (blue) these temperatures are for this time of year. Source: ClimateReanalyzer.org

This surge of heat caused temperatures to soar more than 10ºC above average for this time of year, reaching as high as 45ºC at Villamontes in Bolivia on August 22. According to climate historian Maximiliano Herrera, this was the equal highest winter temperature on record in the Southern Hemisphere.

One day later, the temperature at Nueva Asunción in Paraguay reached 41.9ºC. This was also a new national winter record for Paraguay, says Herrera.

And it’s not just South America that has seen extreme winter temperatures in the past week, with parts of South Africa, Botswana and Namibia also experiencing record-challenging winter warmth.

Australia may also join the list of Southern Hemisphere continents that have places experiencing record-breaking winter heat this month. In Western Australia, Kalgoorlie is forecast to reach 32ºC this Saturday and Sunday. Kalgoorlie’s highest winter temperature on record was 32.0ºC on August 30, 2006. However, it has never had two 32ºC days in winter, with records dating back to 1907.

Image: Forecast maximum temperature in southwestern Australia on Saturday, August 26.