Kelsey Brickl:
(also published as K.M. Brickl or Kelsey Maurine Brickl) is a historian and writer whose work spans historical fiction, essays, and cultural criticism.
Background and education: She’s a graduate of Saint Mary’s College in Indiana, where she studied history and received the Blecka-Zatko Award for Excellence in Senior Composition. She also studied Irish Language and Literature and Irish Studies at the Keough-Naughton Institute at the University of Notre Dame, and completed graduate studies in history at the University of Edinburgh.

In August, an inescapable blanket of heat settled over Paducah ( Kentucky, US ), the last gasping breath of summer roaring its weight out over the populace.

The line describes an oppressive August heat wave smothering the town of Paducah. Breaking down the imagery:
– “An inescapable blanket of heat”
— the heat covers and smothers everything, with no way to escape it (a blanket both covers and suffocates).
– “The last gasping breath of summer”
— personifies summer as a dying creature exhaling its final breath. Since August is summer’s last month, the heat is framed as summer’s final, desperate exertion before autumn takes over.
– “Roaring its weight out over the populace”
— mixes sound (“roaring”) and physical force (“weight”) to make the heat feel like an aggressive, almost violent presence bearing down on the townspeople.
Together, it poetically conveys: in its final days, summer unleashes one last intense, smothering wave of heat onto the town before giving way to fall.
Origin:
This isn’t a traditional idiom or proverb with folk origins — it’s a line of original descriptive prose from a novel. It’s become widely circulated on quote-aggregation sites (Goodreads, various “August” and “end of summer” quote listicles) as a poetic, quotable evocation of late-summer heat, which is likely how you came across it.
Author: Kelsey Brickl
— The quote is attributed to her novel “Paint”. She is also the author of other works, including “Hardtack” ,a Civil War story.