Fresh air at Land's End where it's very dry (4)
I believe the answer is:
arid
'it's very dry' is the definition.
(I've seen this before)
'fresh air at land's end' is the wordplay.
'fresh' is an anagram indicator.
'at' is a charade indicator (letters next to each other).
'end' says to take the final letters.
The final letter of 'land' is 'd'.
'air' anagrammed gives 'ari'.
'ari'+'d'='ARID'
'where' is the link.
(Other definitions for arid that I've seen before include "Very dry; uninteresting" , "Dry and parched, as with regions" , "flat" , "Dry and sere" , "(Of climate) dry" .)