Overview
- National Weather Service offices have issued heat advisories and extreme heat warnings through Thursday for much of southern and central California, putting more than 35 million people at risk of heat‑related illness.
- The heat has shattered multiple records, with downtown Los Angeles recording consecutive 100°F days — the longest October streak on record for that site — and interior highs reaching low‑100s in places such as San Diego County and the inland valleys.
- Forecasters say the pattern is driven by a strong upper‑level ridge, down‑slope offshore winds, and unusually warm ocean temperatures that have weakened the usual marine layer and kept overnight lows in the upper 60s to 70s.
- Local officials have opened cooling centers, urged hydration and work‑safety measures, and warned animal shelters without air conditioning to seek temporary fosters as the heat strains vulnerable people and pets.
- Models show modest cooling beginning Friday and a slight chance of showers Sunday as moisture and swell from Hurricane Rachel approach, but forecasters warn that weekend wind, surf and fire‑weather outcomes remain uncertain and could raise dangerous rip‑current and strong‑wind risks.