It's not very hot all around Costa del Sol? (4)
I believe the answer is:
cool
'costa del sol?' is the definition.
I can't judge whether this defines the answer.
'it's not very hot all around' is the wordplay.
'it's not' becomes 'o' (I've seen this in other clues).
'very hot' becomes 'col' (I can't explain this - if you can you should give a lot more credence to this answer).
'all around' means one lot of letters goes inside another.
'o' going within 'col' is 'COOL'.
Can you help me to learn more?
(Other definitions for cool that I've seen before include "Fashionably attractive" , "Unemotional; excellent" , "Fashionable (but don't lose yours!)" , "Unfriendly; excellent" , "Relaxed; not warm" .)