This phrase is not actually slang, but a proverb meaning that after difficult times, good times always follow. It is similar to the English 'after a storm comes a calm'.
Examples
- Spanish: Después de perder su trabajo, Juan encontró uno mejor. Como dice el dicho, después de la tormenta, siempre llega la calma.
- English: After losing his job, Juan found a better one. As the saying goes, after the storm, calm always comes.