Why is the Ocean water on the west Coast so cold comparing to the East coast?
This is a good overview of ocean surface currents, which includes a schematic like this one:



In the mid-latitudes, you get gyre circulations that move poleward along the eastern coasts of continents (the western edges of the ocean), bringing warm water. The water off the east coasts of these places is thus warmer than you would expect for that latitude. The return flow on the eastern edges of ocean basins (west coast of continents) brings cold water from poleward of that latitude.

There are a few things to note about this circulation, though, since that analysis applies to the mid-latitudes only. There are opposite gyres closer to the poles that make the east coasts much colder than expected. (Compare the Alaska current to the Labrador, which is off the east coast of Canada.) The circulation near the equator is a lot more complex and interesting, especially where it meets up with other gyres.

There are some strange and fascinating reasons why the circulation is the way it is, but that answer is the result of an entire oceanography course...