After the typhoon, the sea water turns blue for a few days

3 to 5 days. After a typhoon, you need to wait until the sea is calm before the water turns blue. This period of time is 3 to 5 days. Typhoon is a type of tropical cyclone. A tropical cyclone is a low-pressure vortex that occurs on the tropical or subtropical ocean. It is a powerful and deep "tropical weather system".