An exclamation similar to for heaven's sake. See under for one's sake, def. 3.
The Origin Of Dog DaysThe exact dates of the dog days depend on your latitude, but by today’s estimation they begin on July 3 and come to a close on August 11.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.