The most common and most likely answer to this crossword clue is the 10 plus 6 letter word WIND-CHILL FACTOR
I've seen this crossword clue in The Guardian
W
I
N
D
-
C
H
I
L
L
F
A
C
T
O
R
Buddy explains!
The straight part
We know that "it’ll make you feel more cool" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case it’ll make you feel more cool = wind-chill factor.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.