Crop in German weather (5)
I believe the answer is:
grain
'crop' is the definition.
(I know that grain is a type of cereal)
'german weather' is the wordplay.
'german' becomes 'g' (abbreviation).
'weather' becomes 'rain' (rain is a kind of weather).
'g'+'rain'='GRAIN'
'in' acts as a link.
(Other definitions for grain that I've seen before include "Particle of e.g. sand" , "bit of corn" , "Pattern of lines in wood" , "Silo contents" , "Small hard particle, of rice perhaps" .)