When it's cool out, run! (7)
I believe the answer is:
control
'run' is the definition.
(I know that run is a more specific form of control)
'when it's cool' is the wordplay.
I cannot really understand how this works, but
'when' could be 'on' (I've seen this in other clues) and 'on' is found within the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
'out' acts as a link.
Can you help me to learn more?
(Other definitions for control that I've seen before include "Manage - government" , "Check" , "Rule" , "Mastery" , "domination" .)