This past Sunday was the warmest single day ever recorded, according to the Copernicus Climate Change Service, the European Union-funded research organization. That is, until Monday, when global temperatures inched up a bit more. Then Monday became the hottest day in modern history, with an average global temperature of 17.16 Celsius or 62.88 Fahrenheit. Tuesday was almost as hot.

The records shouldn’t come as a complete surprise. Earth tends to be at its warmest during the Northern Hemisphere’s summer. The previous record for the planet’s warmest day came last July.

But what stunned scientists wasn’t the temperature of the hottest day ever recorded, which was up slightly from last year, it was how much hotter than usual it’s been during the rest of the year, between these two summer peaks. Instead of returning to something close to normal, average global surface temperatures have remained stubbornly high for more than a year now.

“What is truly staggering is how large the difference is between the temperature of the last 13 months and the previous temperature records,” said Carlo Buontempo, director of Copernicus. “We are now in truly uncharted territory, and as the climate keeps warming, we are bound to see new records being broken in future months and years.”

On Thursday, António Guterres, secretary general of the U.N., addressed the global heat wave and called for new efforts to protect the vulnerable and workers, as well as to make population centers more resilient.

“Let’s face facts,” he said. “Extreme temperatures are no longer a one-day, one-week or one-month phenomenon. If there is one thing that unites our divided world, it’s that we’re all increasingly feeling the heat. Earth is becoming hotter and more dangerous for everyone, everywhere.”