Based on Earth’s tilt and orbit, astronomical summer runs from the to the autumnal equinox :
While the above months are generally considered summer in Australia, the exact timing and duration of summer can vary depending on the region: what month is summer in australia
The most "useful paper" for practical purposes is the official standard provided by the Australian Government's Bureau of Meteorology. This is the document referenced by meteorologists, government agencies, and the media. Based on Earth’s tilt and orbit, astronomical summer
Summer in Australia is characterized by long daylight hours and high heat, particularly in January. Based on Earth’s tilt and orbit