A trip down the Library of Congress photo archive rabbit hole this afternoon led me to a bold claim:

In his 1878 book Picturesque Arizona, Enoch Conklin quotes Dr. A. M. Loryea: “The heat in Arizona, though high, is endurable in consequence of the dryness.” This may be the granddaddy to Arizona’s most quoted weather phrase: “but it’s a dry heat, so you don’t mind it.”

That’s from Jim Turner’s Arizona: A Celebration of the Grand Canyon State.

Conklin was of that curious tradition of 19th century travel writing, and along a intriguing sub-thread suggested by his book’s title. The desert was strange and forbidding to Conklin’s east coast audience:

Yet with the arrival of the Southern Pacific in Yuma (“A more propitious or favorably auspicious event will never probably be known in the history of that territory”, Conklin wrote), the desert was newly accessible in a way it had not been before, and Conklin positioned himself as part of a new literary tradition  when he described it as “picturesque” in his title. It’s a tradition enshrined in the Arizona Highways magazine of my childhood, but it was a fresh take in its day.

I stumbled to him after finding this intriguing image:

Looking up the Colorado River from Ehrenburg
Creator(s): Conklin, E. (Enoch), photographer
Date Created/Published: [S.l.] : Continent Stereoscopic Company, [ca. 1877]

Arizona is the coming land of the artist, as well as of the miner and farmer.