The global record set in December 2015 was also matched, says the EU's climate change monitoring agency.
By midcentury, troops could face an extra month of heat-index temperatures above 100 F every year, the Union of Concerned Scientists found.
Temperatures were 0.69C warmer than the average October temperatures from 1981-2010.
"With continued greenhouse gas emissions and the resulting impact on global temperatures, records will continue to be broken in the future,” warned Copernicus, the EU climate change service.
Using new techniques, researchers have found the rate of rising sea levels has increased year on year since the 1960s. It was previously believed to have begun accelerating in the 1990s.
This shows the UK's average temperatures in selected years. All its hottest years since 1884 have occurred this century.
Watch for the signs of heat illness in scorching summer temperatures.
The heatwave gripping Europe has toppled all-time temperature records in Belgium, the Netherlands and Germany.
Scientists have analysed pairs of 520 major cities around the world and tested to see what their climate in 2050 would look like.
June 2019 has just been confirmed as the hottest month ever on record, according to Copernicus.
In the eastern town of Eglisstadir, temperatures have almost reached 22°C and activities in the sun are in full swing.
Climate scientist Zack Labe told Euronews this phenomenon could cause temperatures to rise over 10°C above average in some areas of Alaska, making the climate feel equivalent to late-summer
From a melting mountain in Sweden, to a surge in beer sales in Germany, find out how the soaring temperatures are affecting Europe.
As temperatures in Europe continue to soar, with forecasters predicting record-breaking heat in the coming days, people across the continent are searching for ways to keep cool.
Portugal’s Met Office has retracted its prediction that temperatures in the country could reach 50ºC — the hottest ever recorded on mainland Europe — this week, drastically revising the forecast down by 10 degrees.
Surface air temperatures have been increasing on a regular basis globally since 1979. On a monthly global average, since 1989, surface air temperatures have been increasing each month every year
Thousands across the world plunged into icy waters to welcome in 2018.