MADRID, Jan 26, 2024 (BSS/AFP) - Spain grappled Thursday with unusually warm temperatures for a winter month as a mass of hot air pushed the mercury to just shy of 30 degrees Celsius (86 Fahrenheit) in some regions.

Temperatures reached or exceeded 20C at nearly 400 meteorological stations -- almost half the country's total --, the spokesman for national weather agency Aemet Ruben del Campo wrote on X, formerly Twitter, calling the figures an "anomaly".

The mercury rose to 29.5C in the eastern region of Valencia, 28.5C in Murcia in the southeast and 27.8C near Malaga in the south -- temperatures usually seen in June not January.

Overnight temperatures have also been warmer than normal.

The mercury did not drop below 10C overnight Wednesday in the small ski resort of Puerto de Navacerrada near Madrid, which is 1,900 metres (6,200 feet) above sea level and is normally covered in snow at this time of year.

The winter heat, which has also affected southeast France, was caused by the presence of a powerful anticyclone above the Mediterranean, said David Corell, a researcher at the University of Valencia.

"There are no studies yet that have evaluated the long-term trend of this type of event but it is clear that we are experiencing this type of abnormal situation more and more frequently," he told AFPTV.

Spain also recorded unusually high temperatures in December, with the mercury peaking at 29.9C in Malaga, a national record for the month.

The heat comes amid a prolonged drought affecting much of the country, especially the northeast region of Catalonia and the southwest region of Andalusia.

In Catalan capital of Barcelona, Spain's second-largest city, water reservoir levels fell in mid-January to around 17 percent of their capacity.

If they fall below 16 percent of their capacity -- which could be imminent -- the region will declare a state of emergency.

As global temperatures rise due to climate change, scientists have warned that heatwaves will become more frequent and more intense.