Heat Extends Beyond Summer, Across Spring and Fall, Study Finds

A 45-year global analysis (AGU Advances) shows extreme heat seasons have expanded into spring and fall across about half the world since the 1980s, with some regions seeing earlier heat and others later, and a noticeable shift in the seasonality of dangerous heat. NOAA reported this summer (June–August) was the warmest in 132 years in the Lower 48, while August globally set a heat and humidity record. While exact causes remain uncertain, climate change is viewed as the primary driver. The timing shifts raise risk because protections are often centered on summer, leaving communities vulnerable when extreme heat arrives off-season or lingers past expectations.