"Now is the ... of our discontent" (Richard III) (6)
I believe the answer is:
winter
(Other definitions for winter that I've seen before include "'If . . . . . . comes, can spring be far behind?'" , "period of freeze?" , "Time for mittens and scarves?" , "'Now is the . . . . . . of our discontent' (Richard III)" , "period of discontent?" .)