During El Niño, warm waters pool in the eastern Pacific, driving hotter weather around the world, amplifying the impact of warming. El Niño drove record heat in 2023 and 2024, the hottest years ever recorded. This year, forecasters say a strong El Niño will take shape between August and October. “El Niño is not just on our doorstep — it is inside the house and turning up the heat,” said U.N. Secretary-General António Guterres. El Niño is strengthening — adding fuel to a planet already on fire with scorching heat domes, apocalyptic wildfires, and record hot seas.”