Rising temperatures should trigger a global "red alert," the United Nations' weather and climate agency chief said after global heat indices again smashed records in August.

The world saw record average temperatures in August for the second year running, preliminary data from the EU's climate monitor seen by Agence France-Presse (AFP) showed.

Australia, Japan, parts of China and Norway all experienced their hottest August on record, according to meteorological agencies.

"It's clear that the temperatures are rising above what we would like," said Celeste Saulo, head of the World Meteorological Organization (WMO).

"And it is because the action is not enough."

While the exact average global temperature for August 2024 is not yet known, the EU's Copernicus Climate Change Service (C3S) has established it will be above the record 16.82 degrees Celsius (62.28 degrees Fahrenheit) measured in August last year.

"Thresholds are all the time being beaten," Saulo said, speaking in Singapore at a regional climate forum of local meteorological services.

Saulo also called for better monitoring and support for meteorological agencies, adding that "we need more resources."

The forum comes days after the WMO released its latest assessment on the impacts of climate change in Asia and the Pacific, warning that sea-level rise is above average in many areas.

And the record August continues a near-unbroken 15-month streak, where each month eclipsed its own temperature record for the time of year, according to the C3S.

The climate forum also announced the designation of Singapore as a regional hub for monitoring pollution caused by vegetation fire and smoke.

One of only two such centers in the world, the facility will offer better quality information on fires and pollution forecasts, plugging a gap in regional data, officials said.