LAS VEGAS — An unrelenting heatwave is scorching southwestern parts of the US with Arizona projected to see a record stretch of extreme hot weather.

More than 115 million people are under some form of heat warnings, the National Weather Service (NWS) said.

Phoenix has experienced 13 days of temperatures of at least 43C (110F) and is forecast to surpass its 18-day record of over 43C heat next Tuesday.

Many other cities are expected to soar above 100F (38C).

In a warning issued on Thursday, the NWS said the heatwave will also hit states like Nevada, Oklahoma, Texas and California.

It expects “oppressive heat” of up to 115F (46C) in some parts of the Southern Plains.

Forecasters say overnight temperatures are expected to remain “abnormally warm” at around 90F (32C) in some areas, offering little night-time relief from the heat.

Officials have urged people to be cautious and limit time outdoors during peak sun hours, to stay hydrated and to not leave pets or children in locked vehicles.

About 700 people are estimated to die each year from heat-related causes in the US, according to the Centers for Disease Control and Prevention (CDC).

Las Vegas, Nevada, is projected to see a high of 117F (47C) on Sunday, which would be the city’s all-time high for its hottest temperature on record, set in July 1942 and matched in July 2021.

In El Paso, Texas, temperatures have been in the triple-digits Fahrenheit for 27 consecutive days, and the extreme heat is projected to continue.

This has surpassed the city’s record of 23 days of consecutive extreme heat, set in 1994.

In Phoenix, cooling shelters have been opened for people who are homeless, while volunteers made wellness calls for seniors and those living on their own.

The city has also given out thousands of water bottles as part of its heat relief program.

The US heatwave comes amid similar high temperatures in Europe, where parts of Spain, France, Greece, Croatia and Turkey are expected to hit above 104F (40C).

In Italy, there have been several reports of people, including tourists, collapsing as a result of the heat. At least one person has died.

Last week, the global average temperature was 63F (17.23C), which is the highest ever recorded.

Scientists say the temperatures are being driven by climate change and the naturally occurring weather pattern known as El Niño, which causes temperatures to rise and happens every three to seven years.

The world has already warmed by about 1.1C since the industrial era began and temperatures will keep rising unless governments around the world make steep cuts to emissions. — BBC