Sydney's western suburb of Penrith recorded the highest temperature in Australia yesterday and possibly Sunday's highest temperature on Earth as well. A stream of hot air from the nation's Interior swept across NSW on Sunday, sending the mercury soaring from Bourke (45.4C) to Bankstown (45.2C). While the highest temperatures in NSW often occur in the state's west, the combination of an exceptionally hot air mass and something called the Foehn effect meant that yesterday's highest temperature was observed on the eastern side of the Great Dividing Range. Penrith's top of 47.3 degrees was the highest temperature officially recorded in NSW and Australia on Sunday. It was also Penrith's hottest day in 23 years of records and the highest temperature recorded anywhere in the Sydney Basin since 1939. Observatory Hill, which is Sydney's official recording station in the city, experienced its hottest day in five years after reaching 43.4 degrees. So, how did Penrith's 47.3 degrees stack up compared to the rest of the world? Australia is one of the first countries on Earth to begin and end each day, due to its position a few thousand kilometres west of the international date line. As a result, some parts of the world were yet to end Sunday at midday on Monday in Sydney. According to reliable temperature observations that were available at the time of writing this article, Penrith's 47.3 degrees appears to be the highest value recorded anywhere in the world on Sunday. In fact, NSW locations appear to have taken at least the top three spots, with Wilcannia's 46.4 degrees and Richmond's 46.3 degrees rounding out the podium for Sunday. It's not unusual for an Australian location to be the hottest place in the world at this time of year. While the southern hemisphere is currently in the middle of summer, the northern hemisphere is in the depths of winter. However, it is quite remarkable that a suburb in one of Australia's capital cities took top spot. Penrith's outstanding heat may have been a daily high, but it didn't challenge all time global records. There are places on the other side of the equator that could make western Sydney's 47.3 degrees seem mild if this were June or July. California's aptly named Furnace Creek in Death Valley is the current world record holder for heat after the site registered a maximum temperature of 56.7 degrees Celsuis in 1913. On Sunday, the mercury only topped out in the mid-twenties at Furnace Creek. Ahwaz in southwest Iran is another one of our planet's known hot spots and has recorded temperatures as high as 53.7 degrees Celsius. Yesterday, the mercury only climbed to 22 degrees in the Iranian city. Australia's highest temperature on record was 50.7 degrees at Oodnadatta in SA during 1960. The highest temperature ever recorded in NSW was 49.7 degrees at Menindee in 1939.