121 plus high humidity and virtually no wind. Coast of Saudi Arabia
Although there are no official records, 178 degrees (81 Celsius) is the highest known heat index ever attained. It was observed in Dhahran, Saudi Arabia on July 8, 2003. In his book Extreme Weather, weather historian Christopher Burt says Dhahran, also on the Persian Gulf, registered an air temperature of 108 degrees (42 Celsius) and a dew point of 95 (35 Celsius), which computes to such an extreme heat index level.
Wherever you live or happen to travel to, never complain about the heat and humidity again. In the city of Bandar Mahshahr (population of about 110,000 as of 2010), the air felt like a searing 165 degrees (74 Celsius) today factoring in the humidity.