Monday was most likely the hottest day ever recorded on Earth, with a global average of about 62.87 degrees Fahrenheit, or 17.15 degrees Celsius, preliminary data showed — beating a record that had been set just one day before.

The data, released on Wednesday by the Copernicus Climate Change Service, a European Union institution that provides information about the past, present and future climate, caused alarm among some experts.

Earlier this week, the service announced that Sunday had set a record, with a global average of about 62.76 degrees Fahrenheit, or 17.09 degrees Celsius. A day later it announced that Monday was the hottest day since at least 1940, when records began.

Before this week’s back-to-back records, the previous record, 62.74 degrees Fahrenheit, or 17.08 degrees Celsius, was set last year, on July 6, besting a record that stood since 2016.

Since Sunday’s and Monday’s temperatures were averages, some portions of the globe felt that extra heat more strongly, like parts of the Western United States where an excessive heat warning has been in place for days and is expected to continue for much of the week.

“What is truly staggering is how large the difference is between the temperature of the last 13 months and the previous temperature records,” Carlo Buontempo, the director of the service, said in a news release announcing Sunday’s record. “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.”