Brisk

Me talking to a teen from Hong Kong visiting Wisconsin for the year:

Him: "It's cold." [1]
Me: "I could get the portable heater out .. but we don't turn on the furnace until it gets down to about 30."
Him: "Celsius?"
Me: "Fahrenheit"

Snicker.

[1] It was down to 58 F outside.  I will allow this is 'brisk', given that it is August.