Seaweed (Caulerpa sp) is a marine biota whose growth is influenced by physical parameters. The purpose of this study was to analyze the dynamics of daily temporal changes in seawater temperature at several depth points and variations in the velocity and direction of ocean currents. Make simple mathematical modeling of ocean current velocity and daily dynamics of seawater temperature in the seaweed growth zone and outside the seaweed growth area. Temperature measurements are carried out on 4 depth variations using a current meter when the sun illuminates the ocean. Measurement of the velocity and direction of the current is carried out using a current measuring instrument during the full moon. The Fourier function or periodic function determines mathematical modeling. The results showed that the transect measurement of sea temperature for 4 depth variations experienced changes due to the intensity of solar irradiation. During one cycle, the speed and direction of the ocean currents change periodically, with the average flow velocity in the seaweed zone being 7.4 m/min and outside the Lahe region being 18.75 m/min directly to the southwest at seawater flows at high tide and northeast experiencing low tide. The daily temporal change in ocean current velocity for each measurement transect shows the same shape which is modeled according to the Fourier function.