Long‑Duration Heat Wave to Shatter Records Across Western U.S.

A powerful high‑pressure system is driving a long‑duration heat wave over the western half of the United States, with forecasters expecting more than 600 record‑breaking daily highs and warm overnight lows through the first half of next week. Triple‑digit temperatures are forecast for the Desert Southwest, and even coastal metros like Los Angeles, San Diego and San Francisco are under extreme heat warnings or advisories through at least Sunday that could be extended. Phoenix is projected to reach 100°F on Wednesday, which would be its earliest 100‑degree day on record, surpassing a mark set on March 26, 1988, in records that date back to 1896. Meteorologists emphasize that heat is the nation’s leading weather‑related killer and are urging residents to hydrate, avoid strenuous activity during peak heat and never leave children in parked cars, noting that hot‑car deaths tend to spike during such events even outside the traditional summer season. The episode highlights how unseasonably early and intense heat can strain public health systems, power grids and outdoor workers across a broad swath of the country.