Across the region, temperatures were 1.9°C higher, and three countries - Estonia, Finland and Latvia - all recorded temperatures 2.4°C higher.
The State of the Climate 2020 report, published by the American Meteorological Society, also showed temperatures in the Arctic continued to rise.
The key findings:
• Earth's greenhouse gases were the highest on record.
• Carbon dioxide levels were at the highest levels.
• The global sea level was the highest on record.
• Earth's warming trend continued.
• The last seven years (2014-20) were the seven warmest years on record.
In Europe, the temperature was 1.9°C above the long-term average, breaking the previous high mark by more than 0.5°C.
“This level of difference to the previous long-term average, which is a large difference, is something that is concerning,” said senior climate scientist Dr Robert Dunn at the UK Met Office.
“It is something to sit up and take notice of, but it's not just the temperatures that are increasing, the extreme events, the heatwaves we're seeing this year, and last year as well. We're seeing these responses across the world.”
In Europe, the five warmest years have all happened since 2014, and 2021 has seen wildfires rage across the continent.
“The amount by which the previous record has been exceeded should worry us all,” said Prof Gabi Hegerl, at the University of Edinburgh.
“European temperatures are well measured and can be tracked back to the beginning of industrialisation and beyond, using documentary evidence and proxy records. This long-term context emphasises how unusual this warmth is.”
July 2021 was the hottest month globally ever recorded, the US National Oceanic and Atmospheric Administration (NOAA) said earlier in August.
“July is typically the world's warmest month of the year, but July 2021 outdid itself as the hottest July month ever recorded,” said NOAA administrator Rick Spinrad.
“This new record adds to the disturbing and disruptive path that climate change has set for the globe,” he said.
Britain has become warmer, wetter and sunnier this century because of climate change, an annual report by leading meteorologists said in July, prompting warnings of record summer temperatures in future decades.
The State of the UK Climate 2020 found that 2020 was the third warmest, fifth wettest and eighth sunniest on record in the UK.
It was the first time that a single 12-month period has registered in the top 10 for all three variables.