There has been a long period without rain - a "dry spell". Normally we can't do anything to make the rain come. So "We will break it soon" suggests that the phrase is being used, as it often is, symbolically, to refer to a long period when something hasn't happened. It could be (often is) a guy, hoping for a date after a long time, or it could be a football team talking about winning a trophy or a match after a long period with no success, or it could be a business manager referring to a long period without a big deal.