Earth's average temperature again reached a record level on Thursday, according to satellite data and computer simulations processed at a US university.

The Climate Reanalyzer at the University of Maine recorded a planetary average of 17.23 degrees Celsius (63 degrees Fahrenheit), beating the record 17.18 C mark reached on Tuesday and Wednesday.

The news comes as the EU's climate monitoring service said Thursday that the Earth had experienced its hottest June on record last month.

The EU monitor Copernicus also said preliminary data showed Tuesday was the hottest day ever recorded.

What scientists say about the climate data

The US National Oceanic and Atmospheric Administration (NOAA) warned that the Maine analysis should be treated with caution and that it could not validate the data.

At the same time, however, it said it recognized "that we are in a warm period due to climate change."

It said that "combined with El Nino and hot summer conditions, we’re seeing record warm surface temperatures being recorded at many locations across the globe."

Although the records are unofficial, many climate scientists regard the findings as very worrying, while UN chief Antonio Guterres has said the new statistics could go to prove that climate change is "out of control."

"If we persist in delaying key measures that are needed, I think we are moving into a catastrophic situation, as the last two records in temperature demonstrates," he said.

The rising temperature of the Earth is being driven largely by human activities, including the use of fossil fuels in transportation and industry, and large-scale livestock farming for food.

Several regions across the globe have been suffering heat waves, including parts of China and the US, while Antarctica has seen temperatures 4.5 C above normal this week.