Cool as a cucumber

Origin of: Cool as a cucumber

Cool as a cucumber

The expression, cool as a cucumber, describing someone as calm and unruffled has been around since the 18th century. Cut cucumbers are indeed cool to the touch and this phenomenon has been known for some time but it was only fairly recently, c. 1970, that scientific measurements were carried out, from which it was discovered that cut cucumbers are some 20 degrees Fahrenheit cooler than the ambient air.