"Rain comes unexpectedly" Dark cloud means rain. Sometimes it comes unexpectedly like problems and challenges in life. Heavy rain can cause floods that destroy our house. While big problems can cause stress for people that can affect their life and sometimes their thinking. They lose hope and become negative. Its like experiencing darkness around without a hope that a single light will come. Rain or problems, be prepared. We may not stop this from coming but we can minimize its effect or damage that will leave in our life. Remember; There's a rainbow comes after the rain and there's a solution to every problem. @Snowver