Cheesey chimed:
colder then a well diggers butt
This is a classically great expression but one that may require explanation for you youngsters.
In the days of yore, wells were dug by hand. As the well digger got completely into ground depth wise, hiss ass would rub against the cold dirt (with I believe is approximately 57 degrees fahrenheit.) This was both unavoidable and provided leverage for continued digging.
Consequently, after a while, the well diggers ass got cold, ergo the expression.
In Luce tua Videmus Lucem KRK