Light rain for most of the season - Kuala Lumpur, mid-September (8)
I believe the answer is:
sprinkle
'light rain' is the definition.
(I've seen this in another clue)
'most of the season kuala lumpur mid-september' is the wordplay.
'most of' means to remove the last letter.
'the season' becomes 'spring' (spring is a season).
'kuala lumpur' becomes 'KL' (common abbreviation).
'mid' indicates the central letters (mid- can mean the middle of something).
'september' becomes 'sep' (short for September).
The central letter of 'sep' is 'e'.
'spring' with its final letter taken away is 'sprin'.
'sprin'+'kl'+'e'='SPRINKLE'
'for' is the link.
(Other definitions for sprinkle that I've seen before include "Scatter small drops, spray" , "Apply drops of water to" , "Disperse in small drops, like water on garden" , "Some 8s [RAINDROP]" , "Scatter finely" .)