"Another year. Another record. The high temperatures we saw in 2015 are set to be beaten in 2016," said WMO secretary-general Petteri Taalas.
"In parts of Arctic Russia, temperatures were 6°C to 7°C above the long-term average. Many other Arctic and sub-Arctic regions in Russia, Alaska and north-west Canada were at least 3°C above average. We are used to measuring temperature records in fractions of a degree, and so this is different," said Mr Taalas.
The report highlights the fact that other long-term climate change indicators are also breaking records. The amount of greenhouse gas in the atmosphere continued on its upward march in 2016.
Arctic sea ice continued to melt in significant amounts, while the Greenland ice sheet displayed very early melting this year.
Experts believe that the El Nino weather phenomenon played a role in the record warm temperatures seen in 2015 and 2016.
They quantify it as roughly 0.2 of a degree - but the bulk of the warming is coming from the accumulation of greenhouse gases. And the impacts of that warming are being widely felt.
"Because of climate change, the occurrence and impact of extreme events has risen," said Petteri Taalas.
"'Once in a generation' heatwaves and flooding are becoming more regular. Sea level rise has increased exposure to storm surges associated with tropical cyclones," he said.