A Record-Breaking Spring Heat Wave Is Making Its Way Across the U.S. Here's What To Know

A historic March heat wave has brought record-breaking temperatures to nearly 180 U.S. cities, with parts of the Great Plains running as much as 45°F warmer than average and California and Arizona reaching 112°F. Scientists attribute the early and intense heat to climate change, which shifts the probability curve of extreme heat days—meaning days that once occurred 5% of the time now happen 10-15% of the time even with modest global temperature increases. Dr. David Eisenman, a UCLA professor studying heat's public health impacts, notes that while this would have been considered "very abnormal" a decade ago, such March warmth is becoming the new normal. Scorching temperatures are expected to persist across the West in coming days before moving eastward, while climate change is projected to lengthen summers and shorten winters nationwide, fundamentally altering seasonal patterns.