Aurora said:Ever heard the one:
"It's colder than a witch's +i+ in a brass bra"
Had never heard the longer version of that (with the bra).
Growing up, I heard the shorter version a lot (grew up in Wisconsin, where it does get a mite bit nippy from time to time), as well as:
"Colder than a welldigger's [heinie]"
"Colder than a brass monkey" (apparently wearing a witch's brassiere)