The question does not ask about how far can the eye see on a curving surface. The asker stated 'a flat surface' Since when in mathematics do we mix up a flat surface with a curved surface. You have turned a very simple question in to a complicated question by introducing a curved plane.
As one would expect, the further you travel from the Equator, the colder the ocean waters generally become. Near the Equator, surface water temperatures can be as high as 80Â° Fahrenheit (27Â° Celsius). Near the poles, the temperature drops to a chilly 28Â° Fahrenheit (-2Â° Celsius). The western side of oceans are usually warmer than the eastern side. This is due to the way in which both the atmospheric and oceanic currents move water from the equator towards the poles on the western side of oceans, and from the poles towards the equator on the eastern side of oceans.
The average ocean temperature is in the high 70âs. Roughly speaking, there are two seasons: from November through April the climate is cooler and more humid, with daily high temperatures of about 81Â°F and lows of 65Â°F at night. More rain falls during the cooler season, but there are also many lovely sunny days. From June through October the climate is warmer and drier with daily high temperatures of about 84Â°F and lows of 70Â°F at night. Most people divide the year into two climate periods - the Dry Season and the Humid Season.