Shorten ascent on a tor in Cornwall primarily due to the weather (8)
I believe the answer is:
climatic
'primarily due to the weather' is the definition.
I can't judge whether this defines the answer.
'shorten ascent on a tor in cornwall' is the wordplay.
'shorten' means to remove the last letter (I've seen 'shortened' mean this).
'ascent' becomes 'climb' (climb is a kind of ascent).
'on' says to put letters next to each other.
'tor in cornwall' becomes 'tic' (this might be a standard abbreviation which I don't know about).
'climb' with its final letter removed is 'clim'.
'clim'+'a'+'tic'='CLIMATIC'
Can you help me to learn more?
(Other definitions for climatic that I've seen before include "Relating to the weather" , "of prevailing conditions" , "Like the weather" .)