It’s not the heat, it’s the (lack of) humidity. Dr. Jeff Masters posted an interesting article in Weather Underground today discussing a potential new record low humidity record for the world, set in Iran.  However, there is another contender for the record from Needles CA in May 2014, with a temperature of 102 F and a dew point of -32 F, giving a relative humidity of 0.33%. You can read the discussion at https://www.wunderground.com/cat6/world-record-low-humidity-116f-036-humidity-iran.

Source: Yinan Chen, Commons Wikimedia