September 2026 was world's 2nd-hottest September on record

September 2026 was the world's second-hottest September on record, with global temperatures 1.63°C above pre-industrial levels as the Pacific Ocean continued to heat up under a strengthening El Niño. It was the second consecutive month to cross 1.5°C mark, after August. September fell short of becoming warmest September in history, as it was just 0.11°C cooler than September 2023.