The US National Centres for Environmental Prediction made the announcement of the record shattering temperatures, saying on average the mercury hit 17.01°C, beating a previous record of 16.92°C in 2016. It follows months of record breaking temperatures around the world.
In the past month, China has been scorched by four severe heatwaves, while hundreds have died due to extreme heat in India.
North America has also been in the grip of wildfires, nearly 20,000 this year, according to the National Interagency Fire Centre. It has led to worsening air quality for around 100 million people amid tinder dry conditions in forests.
In May, Dhaka in Bangladesh recorded its hottest temperature in 60 years, at 40°C, triggering power cuts and forcing schools to close.
Records were also broken over the spring in Thailand, Vietnam and Myanmar while in Seville, Spain, temperatures hit 45°C last month – the worst heatwave in June for 20 years.
The southern US is also suffering under what climate scientists call a “heat dome”, with New Orleans experiencing 43°C, putting at least 1,200 people in hospital in Louisiana since April.
“Unfortunately, it promises to only be the first in a series of new records set this year as increasing emissions of [carbon dioxide] and greenhouse gases coupled with a growing El Nino event push temperatures to new highs,” said Zeke Hausfather, a research scientist at Berkeley Earth.
In North Africa, already in the grip of drought which has impacted crop production and led to record wheat imports, temperatures have reached 50°C.
In the central Middle East, Syria and Iraq are also in the grip of severe drought, although both countries saw bumper harvests over the spring.
Levels in the Tigris and Euphrates rivers are falling, dramatically worsening water quality in southern Iraq and leading to an incident of mass fish death earlier this week in Maysan province, near Iran.
Diplomatic tensions are growing between Iraq and its neighbours Iran and Turkey, who have dammed the headwaters of the two critical rivers.