Second Hottest Year on Record, says BOM Many farmers are facing hot, dry conditions. Photo: Steve Hynes Australia's run of exceptionally warm weather has extended into May, giving the country its second-hottest start to the year on record. The first four months of 2013 have seen average national daily maximum temperatures reach about 1.33 degrees above the average for 1961-1990, shy only of the blisteringly hot start to 2005, according to the Bureau of Meteorology. Compounding the warmer-than-usual conditions, much of the grain belts of NSW, Victoria and Western Australia posted below or very-much-below-average rainfall last month. "The failure of the autumn [rain] break - this is what really worries the cereal croppers," Karl Braganza, manager of climate modelling at the bureau, said. Australia posted its hottest summer in more than a century of records over the December-February period, even without a dominant El Nino weather pattern over the Pacific - the conditions which typically produce exceptionally warm temperatures over much of the country. In fact, a slew of other records have tumbled in 2013, including the hottest day and hottest month. The 11 months from June to the end of April were also the country's hottest for maximum temperatures, underscoring the persistence of unusually high mercury readings. Late-season heat records have also tumbled, including the latest maximums above 45 degrees. "Since November, we've had slow-moving weather patterns bringing a series of heatwaves," Dr Braganza said. It's part of what makes this period interesting in terms of the background warming. Climate scientists say the planet is heating up as greenhouse gases emitted by burning fossil fuel or from land-clearing trap more of the sun's heat. May warmth Sydney and Melbourne, along with much of the country, registered a warmer-than-normal April, a trend that looks likely to extend into May. Sydney, for instance, is expecting a maximum of 25 degrees on Wednesday, well above the mean maximum of 19.4 degrees for the city. Daily maximums should range from 21-25 over the next week. Melbourne, meanwhile, is likely to see a top of 17, compared with May's mean maximum of 16.7 degrees over the long term. Each of the next six days, though, should see temperatures reaching 18-20 degrees, the bureau said. In coming days, parts of WA and South Australia are likely to see temperatures as much as 10 degrees above average for this time of the year. While weather fronts will weaken the high pressure system as it moves east, parts of Victoria and NSW can expect temperatures to rise to 2-4 degrees above normal between Wednesday and Saturday, Dr Braganza said. Adelaide can expect the mercury to spike 6 degrees above average. The end of April was also notably warm. Sydney's four-day run of 26 degrees or warmer weather from April 26-29 was the second hottest spell so late in the season in 150 years of records, lagging only 1968, according to Weatherzone. "This is mainly due to dominant high pressure systems bringing clear skies and allowing heat to build inland, while preventing any strong fronts from reaching Sydney," Melissa MacKellar, a Weatherzone meteorologist, said. Dry times There's also little rainfall relief in sight for the dry farming regions of south-eastern Australia, with the bureau last week predicting below-average rainfall for much of Victoria and Tasmania over the coming three months. In recent years, the eastward movement of cold fronts has tended to shift pole-ward in the southern hemisphere. In Australia's case, that means more of them are missing the continent. "These fronts just aren't bringing the same amount of rainfall," Dr Braganza said. For Melbourne and Sydney, April saw contrasting rainfall for April. Sydney's Observatory Hill station recorded 199.8 millimetres, about 50 per cent above the average for the month. Melbourne, often derided as a damp city, posted just 27.2 millimetres of rain, a little over half the average of 52.7 millimetres for the month. Weatherzone is owned by Fairfax Media, publisher of this website.