Brass monkeys

[Peter Mabey]

I'm surprised that Susie gave credecence to the 'polite' explanation of "cold enough to freeze the balls off a brass monkey".
According the Royal Navy archives, there is no evidence that cannon balls were ever stored on brass plates called 'monkeys'. In any case, if such were made with so little margin of safety that the differential contraction of brass and iron would dislodge the balls, they would certainly not stay in place in even a moderate sea.
The true origin is likely related to the contraction of the scrotum in the cold, and the fact that the brass statuettes mentioned by Susie are cold to the touch, and depicted without genitals.

[Charlie Reams]

It reminds me of "Situation Normal All Fouled Up", or her highly circumspect definition of FANNIES. It's quite charming really.

[Jennifer Turner]

Well, she did say that the three wise monkeys were the most likely origin, but she was a bit wishy-washy about it. And since when has the phrase been, as Susie says, "cold enough to freeze the tail off a brass monkey" anyway?

[Lucy Gowers]

I thought she was right to be circumspect as the etymology of the phrase is fairly unclear.

The earliest citations of the tail variant date from the 1850s and have been recorded in the OED since about 1929 which would suggest a fair degree of usage in the late 19th Century/early 20th Century.