In June the rates will be lower (6)
I believe the answer is:
nether
'be lower' is the definition.
(as in nether regions)
'in june the rates' is the wordplay.
'in' indicates a hidden word.
'NETHER' can be found hidden inside 'june the rates'.
'will' acts as a link.
(Other definitions for nether that I've seen before include "inferior" , "Underground" , "Lower in position" , "These regions are beneath" , "North European country" .)