Miami Beach weather essentials. Miami Beach, Florida has great weather year-round with warm and sunny days and breezy tropical nights. Miami boasts the warmest ocean temperature in the United States mainland - making it the perfect spot for a beach vacation 12 months a year. Bring your sunglasses, bathing suite, and beach towel and you’re ready to relax and enjoy the tropical climate of Miami. November through mid April is the most popular time to visit Miami, as this is the cold season in the rest of the United States.