It borders on the impossible, in fact, for things to get much drier than this:
On Tuesday afternoon at 12 UTC on June 20, 2017, the temperature at Safi-Abad Dezful, Iran hit 115.7°F (46.5°C) with a -27.8°F (-33.2°C) dewpoint, giving this city of 420,000 in western Iran a ridiculously low relative humidity of 0.36%. At that level of atmospheric moisture, the temperature would have had to plunge 143°F (80°C) in order for the moisture to condense out and form ground-level clouds. If one were to cry in joy (or more likely) in despair at the heat, I doubt those tears would reach your lips!
I asked weather records expert Maximiliano Herrera about the reading, and he stated that he confirmed the validity of the reading with Iranian meteorologist Sabit Siddiqi. This was the lowest humidity in world recorded history that Herrera was aware of; the previous lowest humidity he knew of was in Las Vegas, Nevada: a 0.6% reading on June 27, 2011.
There’s apparently one more reading in this ballparK:
[O]n May 4, 2014, Needles, California hit 102°F (38.9°C) with a -36°F (-38°C) dewpoint, which works out to a relative humidity of 0.33%. Given that we can’t really measure humidity to a precision of hundreths of a percent, the two readings are pretty much tied for the lowest humidity record.
A dew point of 35°C (95°F) was observed at Dhahran, Saudi Arabia, at 3:00 p.m. on July 8, 2003.
God bless you, Willis Carrier.