Peter out in gusty weather getting led astray outside (7)
I believe the answer is:
dwindle
'peter out' is the definition.
(I've seen this before)
'gusty weather getting led astray outside' is the wordplay.
'gusty weather getting' becomes 'wind' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'astray' indicates an anagram.
'outside' indicates putting letters inside.
'led' is an anagram of 'dle'.
'wind' placed within 'dle' is 'DWINDLE'.
'in' is the link.
(Other definitions for dwindle that I've seen before include "go down" , "Diminish - shrink slowly" , "Grow less and fade away" , "Grow less - waste away" , "Become steadily less" .)