Stop period of cold weather (6)
I believe the answer is:
freeze
This clue is a double definition.
'stop' is the first definition.
(thesaurus)
'period of cold weather' is the second definition.
(I've seen this before)
(Other definitions for freeze that I've seen before include "Turn to ice" , "Suddenly become still" , "Harden into ice" , "Change to ice" , "Suspend" .)