If my memory serves me correctly, Hopetoun, Victoria reached 49°C (≈120°F) in 2009. Mildura, Victoria, during the same year, experienced twelve consecutive days over 44°C (111°F). It's difficult to maintain average levels of productivity when temperatures exceed 45°C. Particularly when said temperatures are either a) coupled with strong, hot northerly winds &/or b) you're required to do anything outdoors. Though what I've found to be more challenging, or at minimum, difficult to overcome in addition to, is combating the sleep deprivation caused by the consecutive nights of temperatures greater than 37-ish°C (98 °F). When available, thank the Goddess for air-conditioning. When temperatures are this high, consistently, for weeks at a time, odd things begin to happen. For instance, if friends & family aren't bordering heat stroke, or near catatonic with heat induced lethargy, they're either extremely short tempered or in the foulest of moods. Arguments breakout left right & centre. Heat haze & all manners of mirage reliably plague distant objects. Many forms of infrastructure droop as though stretched beyond their means. Birds faint & fallout of trees. And sometimes koalas, too. Indoor candles melt despite never being lit. Roads & driveways liquify or deliquesce, leaving the awful tar-like scent of rich bitumen in the air. And if you're driving through the outer suburbs or rural areas, it's common to see snakes convulsing on the side of asphalt roads, as the temperature of the road—baked by the relentless Aussie summer sun—induce seizures. And then there's the thick blanketing smoke & wild fires. I guess what I'm trying to say is, if you haven't an affection for hot weather, you will want to avoid southeastern Australia between early January to late February, early March.