Fahrenheit and Celsius
"oh" and "ah"
Fahrenheit and Celsius
Weight, mass, pull and Newtons
'North' and 'South' are.
Kelvin, Celsius, and Fahrenheit are the last names of the people who are associated with temperature.
Vagrant youth.
latitude and longitude
Polar air and maritime tropicalnair
words associated with publishing
A temperature inversion is associated with a layer of warm air trapping cooler air near the ground.
The phrase "post office" is a clever answer to the riddle, as it consists of two words and is associated with the handling of thousands of letters (mail). The play on words highlights the difference between literal and figurative interpretations of "thousand letters."
Polar air and maritime tropicalnir.