“It’s not the heat, it’s the humidity” is a well-worn phrase in Florida,
But it’s always struck me as being incomplete, in absolute terms, and also relatively so.
Surely there must be a more sensible way to word it?
Compare that to trying to fill up a 12 oz can from water vapor from the Florida sky. By my calculations it takes 115 barrels of sky, or “sun barrels” as I call them, to fill up that 12 oz can.
That’s not much water in absolute terms, but relatively speaking it’s a bucket full.
The higher the relative humidity, the more difficult it is to sweat, thus making it difficult to cool down.
In Florida, relative humidity runs around 65 percent in the mid day sun, and hovers in the 90s come night time. Compare that to soaring mid day Phoenix sun of 110º F with a relative humidity of 20 percent.
Or as Arizonans say – “It’s a dry heat.”
Not surprisingly it’s called sensible heat index.
That gives Florida’s typical mid summer day of 90º F and 60 percent relative a sensible heat reading of 100º F.
“It’s not the absolute heat, nor is it the relative humidity, but rather a sensible combination of the two.”