I haven't seen a reply yet to this, so here goes . . .

The oldest ASHRAE handbook on my shelf is a 1972 HOF (thanks Bob H.!).
Chapter 33 is Weather Data and Design Conditions. The reference list
includes these two primary sources:

Evaluated Weather Data For Cooling Equipment Design, Addendum No. 1,
Summer and Winter Data (Fluor Products Company, Santa Rosa, Calif., 1964).
and
Engineering Weather Data (Army, Navy, and Air Force Manual TM 5-785, 1963).

You can buy a copy of the 1958 edition of Evaluated Weather Data on amazon
https://www.amazon.com/Evaluated-Weather-Cooling-Equipment-Design/dp/B000HDSNFY

I bet someone out there has a copy of the Engineering Weather Data
manual on a shelf. Some quick searching leads to this later online version.
http://web.utk.edu/~archinfo/EcoDesign/escurriculum/weather_data/weather_data_summ.html
which says:

"The Engineering Weather Data (EWD) and other products were developed by
the Air Force Combat Climatology Center (AFCCC). Data is provided for
approximately 800 stations worldwide. Intended to support design and
construction of DOD facilities, the format is slanted toward
professional engineers, but could have numerous other uses. "

Searching AFCCC leads here to a fascinating history.
https://www.airweaassn.org/Library/afwa/history.html

"The mission of AFCCC is one of military applied climatology. We
collect, maintain, and apply worldwide weather data, creating
climatological products to strengthen the combat capability of America's
warfighters. AFCCC's support to America's warfighters has a long history."

And a fitting excerpt on the 75th anniversary of D-Day:

"There was probably no WWII operation, major or minor, that did not
include climatological input. The planning for every landing, mission,
and offensive, including the D-Day invasion in 1944 and the atomic
bombing of Japan, required extensive climatological preparation and
analyses."

So, Chris, your impression appears correct. Weather data statistics were
motivated by military requirements (for better or worse), and marketing
cooling equipment.

Mike

p.s. The pages from the 1972 HOF are included in a digitized NBSLD
manual (one of the great mother programs of building simulation), pdf p.
287ff.
https://www.govinfo.gov/content/pkg/GOVPUB-C13-9bcc6856169c63cf2c5ab81af189bd75/pdf/GOVPUB-C13-9bcc6856169c63cf2c5ab81af189bd75.pdf