Snow traveller goes outside tavern when it's not so heavy (8)
I believe the answer is:
skinnier
'it's not so heavy' is the definition.
I can't judge whether this definition defines the answer.
'snow traveller goes outside tavern' is the wordplay.
'snow traveller' becomes 'skier' (I can't justify this - if you can you should give a lot more credence to this answer).
'goes outside' means one lot of letters goes inside another.
'tavern' becomes 'inn' (I've seen this in another clue).
'skier' enclosing 'inn' is 'SKINNIER'.
'when' acts as a link.
Can you help me to learn more?
(Other definitions for skinnier that I've seen before include "Less bulging" , "Not as fat" .)