How hot can it get?

 

I would not want to experience this condition in person.

Hot-tub-like Persian Gulf fuels 158-degree heat index in Iran

"In coastal Iran on Tuesday [August 8], 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.

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."

People that say there isn't a climate change crisis don't live in places like this. 

It's also the highest sea surface temperature on August 7 in the Persian Gulf in a 20-year record, rising fairly steadily from a 2009 minimum in that span.