Europe's summer, from June to August, was 2.5 degrees warmer than the average for the past ten years, according to a report from the EU's Copernicus climate service. The record heat has killed tens of thousands of people across the continent.
More than half of Europe baked under a severe heatwave, with temperatures topping 38 degrees. On 17 days this summer, at least 60% of Western Europe saw temperatures above 30 degrees.
Summer weather set in unusually early, as far back as late May, and high temperatures returned again in September.
Rivers across the continent fell to their lowest summer levels in three decades. The surface temperature of Europe's seas also hit a record high.
The heat and widespread drought fed the spread of massive wildfires. The scorching temperatures also caused water shortages, disrupted energy and transport systems, and wiped out crops.
El Niño is growing stronger than ever, pushing up temperatures worldwide and driving extreme weather from South America to Australia.
The report says warming seas will cause nearly half a million extra heat deaths by February next year.