With Sydney forecast to hit 28 yesterday and Melbourne nudging 25, it's hard to believe winter is five days away. The unseasonal warmth follows months of exceptionally mild temperatures, with Sydney on track for its hottest autumn on record. The heat has been particularly unusual during May, with average maximum temperatures the hottest on record. This includes an unprecedented warm spell of 17 consecutive days above 22 degrees for Sydney, eclipsing the 2007 record of nine days. And the mercury is set to stay above 22 degrees for the rest of the working week. Most of south-eastern Australia have been experiencing an Indian summer over the last two weeks. Yesterday was Adelaide's 16th consecutive day over 20 degrees. Meanwhile, Brisbane is baking in record late autumn warmth, with daytime temperatures exceeding 26.5 degrees since last Friday. Sydney rainfall has also been scarce, with just 25mm for the month, one-fifth of the long-term May average. Gardens will receive a much-needed top-up of rainfall this weekend as a low pressure system tracks across most of South Australia, Victoria and New South Wales from Friday to Sunday. The odds are that the unusually hot and dry conditions will persist not only through this winter and spring, but also potentially into 2015, in large part due to a developing El Nino. El Nino is one half of a climate phenomenon that has far-reaching impacts on weather around the globe. In Australia, El Nino is the "dry" one, usually associated with below-average rainfall in south-eastern Australia and more prolonged and severe bushfires. Over two-thirds of El Nino events since 1900 have caused major drought over large parts of the country. The flip side La Nina is the "wet" one, responsible for the record floods across eastern Australia from 2010-2012. The likelihood of an El Nino coupled with the general trend of warming temperatures in Australia have the potential to make 2014 and/or 2015 our hottest yet, with fears of an earlier and more intense bushfire season. *Magdanela Roze (@magdalena_roze) is a journalist and meteorologist