A new report points to cases in Australia and Iran as warnings that high temperatures and increased humidity may do little to curb outbreak. “There have been 10 influenza pandemics in the past 250-plus years — two started in the Northern Hemisphere winter, three in the spring, two in the summer and three in the fall,” the report said. “All had a peak second wave approximately six months after emergence of the virus in the human population, regardless of when the initial introduction occurred.”