1. The tidal level rises to the highest at 6: 00 a.m. and at 18: 00 p.m. on the first and fifteenth day of each lunar month, and drops to the lowest at 12: 00 a.m. and 0: 00 a.m.. Then the time of high tide and low tide is delayed for 48 minutes every day.

2. The law of seawater fluctuation is: there are two high tides every day, with an interval of 12 hours. The high tide generally lasts for more than an hour before the low tide begins, and the low tide time is at least between the two high tides.

3. The time of high tide is different every day,/kloc-comes back every 0/5 days. Therefore, the climax of the next day is 0.8 hours (48 minutes) later than that of the previous day, and the daily climax time can be calculated according to the lunar calendar date.