As heatwaves sizzled around the world and wildfires engulfed parts of the Mediterranean, Russia and Canada, the global average surface air temperature rose to 17.15 degrees Celsius (62.87 degrees Fahrenheit) on Monday.
That was 0.06 C (0.11 F) higher than Sunday's record according to the EU's Copernicus Climate Change Service, which has tracked such data, opens new tab since 1940, Reuters reported.
This includes temperatures in the Southern Hemisphere which is currently in winter, bringing down the worldwide average.
Scientists said it was possible that Tuesday or Wednesday of this week could again surpass Monday's record, as temperature peaks generally happen in clusters.
The last record hot day was in July 2023, when the daily peak was broken across four consecutive days from July 3 through 6. Before that, it was set in August 2016.
What makes this year's record unusual is that unlike in 2023 and 2016, the world in April moved out of the El Nino climate pattern which generally amplifies global temperatures owing to warmer-than-usual waters in the Eastern Pacific.
Karsten Haustein, a climate scientist at Leipzig University in Germany, said it was remarkable that the record had been breached again now with the world well into the "neutral" phase of the El Nino-Southern Oscillation.
This points to the greater-than-ever influence of climate change, driven by the burning of fossil fuels, in boosting global temperatures.
"This past Monday might have set a new global record for warmest absolute global average temperature ever - by that I mean going back tens of thousands of years," Haustein said.
SD/