Covering for one cold walkabout? (6)
I believe the answer is:
icecap
'covering' is the definition.
(I have seen 'Polar covering ' mean 'icecap' so perhaps 'covering' could also mean 'icecap')
'one cold walkabout?' is the wordplay.
'one cold' becomes 'ice' (I've seen this before).
'walkabout?' becomes 'cap' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ice'+'cap'='ICECAP'
'for' acts as a link.
(Other definitions for icecap that I've seen before include "Frozen polar area" , "Frozen top of mountain etc" , "Permanent coating of white on a mountain-top" , "Frozen topping" , "Permanent frozen polar cover" .)