The United States sweltered in dangerously hot weather on Sunday, with major cities including New York, Philadelphia and Washington broiling in temperatures rising into triple digits.

Australia continued a string of ‘hottest ever’ months in March, the government said Monday, as global warming emerges as the hot button issue in national elections just weeks away.

Hundreds of firefighters were battling two major blazes in northern Portugal on Tuesday, forcing authorities to shut schools and close roads.

As western Europe enjoys record highs for winter temperatures, southern parts of the continent are being hit with snow flurries.

A firefighter has died while battling an enormous wildfire in northern California, authorities said late on Monday.

Temperatures on Thursday reached 35.1 degrees Celsius at Wisley, in Surrey, southern England, officially making it the hottest day of the year so far.

In the week to Sunday at least 65 people died of heat stroke while 22,647 people were hospitalised, the Fire and Disaster Management Agency said.

Officials said last week that the heatwave in Japan had killed at least 15 people and forced the hospitalisation of over 12,000 others in the first two weeks of July.

In Sweden, where temperatures are the highest for a century, farmers are even sending their animals to slaughter.

Temperatures have risen since Monday night and the cooling winds from the Arabian Sea have stopped.

Different parts of the country experienced hot conditions on Saturday with southerly fresh to strong winds causing blowing dust and low visibility, which dropped to below 3km in some areas.

The weather office said northwesterly fresh to strong winds are expected to affect the country from Friday night until Tuesday.