Northern Hemisphere heat waves

A view of the Madeira River amid the drought in Porto Velho in the state of Rondonia, Brazil. With a heatwave in the southern hemisphere and record ocean temperatures, the ominous signs of climate change continue. This year, the Earth's surface registered the hottest temperature in history, exceeding centuries-old records in numerous regions.

Another heatwave is expected to push temperatures in many parts of Greece above the 40 degrees Celsius mark again this weekend, though forecasters are promising cooler weather at the start of next week.

A red code for extreme heat has been issued for the majority of major Italian cities amid an intensifying heat wave across Europe, the BBC reported.

Temperatures are expected to peak on Wednesday, with the warning in place for 23 cities, from Trieste in the northeast to Messina in the southwest.

Code red means the heat is a danger to everyone, not just vulnerable groups.

Tens of millions of Americans were facing dangerously high temperatures Friday as a powerful heat wave stretched from California to Texas, with its peak expected this weekend.

A heat dome has been baking the southwestern states all week, posing serious health risks to the elderly, construction workers, delivery workers and the homeless.

Summer has just begun in the Northern Hemisphere but a brutal heat wave is already gripping parts of Europe, China and the United States, where record temperatures expected this weekend are a stark illustration of the dangers of a warming climate.

Spain sweltered under an unrelenting heat wave Wednesday as temperatures started to build toward what is forecast to be a torrid weekend across southern Europe.

Greece is bracing for its first heatwave which is forecast to hit the country in the middle of next week, as hot air from North Africa will start affecting temperatures from Wednesday, reaching up to 40 degrees Celsius (104 Fahrenheit) in some regions of the country.

The average global temperature hit a new high on Monday, July 3, surpassing the planet-wide average of 17 degrees Celsius for the first time, the BBC reported on Wednesday.

US researchers said the new record is the highest since systematic records of daily temperatures have been kept since the late 19th century.

Last month was Britain's hottest June on record, the country's National Weather Service said on Monday, warning that human-caused climate change is making such temperature records increasingly likely.

Temperatures in Beijing increased above 40 degrees Celsius on Thursday for the first time since 2014, breaking the record for the hottest day in June and the Chinese capital warned of extremely hot weather over the weekend, Reuters reported.