A study led by Weilin Liao and Xuanzong Zhang at Sun Yat-sen University introduces a novel approach to analyzing extreme heat by breaking it down to an hourly level, rather than relying on daily averages. The researchers defined "hourly heat extremes" (HHEs) as temperatures exceeding the 90th percentile for that specific hour of the day, based on historical data from 1981 to 2010. This method reveals that the global average of 270 HHEs per summer has been increasing by 62 hours each decade, a trend that daily metrics often mask.