Losing temperature, turning arctic more or less (5)
I believe the answer is:
circa
'more or less' is the definition.
(I've seen this before)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for circa that I've seen before include "Close to" , "(Especially of a date) approximately" , "About (a time)" , "Costa del Sol city" , "Preceding a date, this means about" .)