。
Tomorrow is another day.
Literal
Tomorrow [topic-は] tomorrow [possessive-の] wind [subject-が] blow.
明日は明日の風が吹く is a well-known proverb — literally 'tomorrow, tomorrow's wind blows.' It means 'don't worry about tomorrow; things will work out on their own.' The repetition of 明日 (first as topic, then as possessive modifier) creates a philosophical tautology: tomorrow has its own nature.