Donald Edwin Westlake:
(July 12, 1933 – December 31, 2008).
American writer with more than one hundred novels and non-fiction books to his credit. He specialized in crime fiction, especially comic capers, with an occasional foray into science fiction and other genres. Westlake created two professional criminal characters who each starred in a long-running series: the relentless, hardboiled Parker (published under the pen name Richard Stark), and John Dortmunder, who featured in a more humorous series.

The August sun, God’s blood blister.

It’s a comic-noir bit of imagery — a “blood blister” is that painful, swollen, dark-red pocket that forms under skin after a hard knock. Comparing the blazing August sun to “God’s blood blister” turns the sun into something angry, throbbing, over-ripe, and faintly grotesque rather than cheerful — the kind of oppressive, sickly-red, punishing heat that makes a New York summer day feel like a low-grade injury inflicted from above. It’s characteristic Westlake: A wry, hardboiled twist on a familiar image (sun = warmth/life) into something bruised and uncomfortable, fitting the exasperated, put-upon tone of his Dortmunder capers.
Author/origin:
Donald E. Westlake (1933–2008), the American crime novelist best known for the Parker novels (as Richard Stark) and the comic Dortmunder heist series. This particular line comes from “Watch Your Back!” (2006), one of the later Dortmunder books. It’s since been recycled widely in “August quotes” listicles, usually stripped of its context.