Fueled by water temperatures in the upper 90s (upper 30s Celsius), the Persian Gulf region is enduring a brutal combination of heat and humidity that is making it feel intolerable.

In coastal Iran on Tuesday, the heat index leaped as high as 158 degrees (70 Celsius), a level so extreme that it can test the ability of humans to survive outside for more than a few hours.

According to MSN, Heat indexes have regularly surpassed 140 degrees (60 Celsius) in the region in recent weeks, while nights have offered little relief. In populous cities such as Abu Dhabi in the United Arab Emirates and Kuwait City, heat indexes have only fallen to 100 to 120 degrees (37.8 to 48.9 Celsius) after dark.

Excessive heat is very much the norm in this region, but it is now particularly intense as the planet reaches its highest temperatures on record. In recent days, Persian Gulf sea surface temperatures have risen as high as 97.6 degrees (36.4 Celsius), the highest in 20 years of satellite data at this time of year.

The hot tub-like waters are similar to those recently observed near the Florida Keys as oceans worldwide set records for warmth. This summer has featured unusually extended spells of scorching weather in the Middle East as zones of high pressure — known as heat domes — have sprawled across a region from North Africa through southern Europe and South Asia.

August opened with a two-day countrywide shutdown in Iran as temperatures soared to at least 126 degrees in the Khuzestan province. The southern Iraq city of Basrah was similarly hot. Temperatures also soared past 124 degrees (51 Celsius) in Ahvaz, Iran, which holds the record for Asia’s highest temperature, 129 degrees (54 Celsius) in 2017.