Arctic sea ice has also melted earlier and faster than usual, another indicator of climate change, says the organization. "Another month, another record. And another. And another. Decades-long trends of climate change are reaching new climaxes, fueled by the strong … El Niño," WMO Secretary-General Petteri Taalas said.
The report details these four areas of concern:
The average temperature in the first six months of 2016 was 1.3°C (2.4°F) warmer than the pre-industrial era in the late 19th century, according to NASA.
NOAA said the global land and ocean average temperature for January–June was 1.05°C (1.89°F) above the 20th century average, beating the previous record set in 2015 by 0.20°C (0.36°F).
Each month was record warm. Most of the world's land and ocean surfaces had warmer to much-warmer-than-average conditions.
The El Niño event which developed in 2015 and was one of the most powerful on record contributed to the record temperatures in the first half of 2016. It dissipated in May.
WMO uses datasets from NOAA, NASA GISS, the UK's Met Office and reanalysis data from the European Centre for Medium Range Weather Forecasting (ECMWF) to calculate global temperature statistics for its annual state of the climate report.
Arctic Sea Ice
The heat has been especially pronounced in the Arctic, resulting in a very early onset of the annual melting of the Greenland ice sheet and Arctic sea ice. Snow cover in the northern hemisphere was exceptionally low. The ice extent as of 20 July was very close to the lowest ever for this date.
The extent of Arctic sea ice at the peak of the summer melt season now typically covers 40 percent less area than it did in the late 1970s and early 1980s. Arctic sea ice extent in September, the seasonal low point in the annual cycle, has been declining at a rate of 13.4 percent per decade.
Rainfall in June 2016 varied significantly around the world. It was notably drier than normal across the western and central contiguous USA, Spain, northern Colombia, northeastern Brazil, Chile, southern Argentina, and across parts of central Russia.
Wetter-than-normal precipitation was observed across northern Argentina, northern and central Europe, much of Australia, and across central and southern Asia.
From January to 4 July, China saw 21.2% above average precipitation. South China entered the flood season on 21 March, 16 days earlier than normal and more than 150 counties were record wet, according to the China Meteorological Administration. More than 300 rivers crossed the water level warning mark.
Temperatures in the Coral Sea (including the Great Barrier Reef), and the Tasman Sea were highest on record for extended periods since late summer 2016, according to Australia's Bureau of Meteorology.
There has been widespread bleaching of reefs in many other parts of the world.