We can read two kind of current information : the usual “tidal streams” diamonds or arrows and the Ocean current. “Weather conditions may considerably affect the tidal streams” in various areas, as written on notes. So much affected that they can run into the same direction for more than a day in Cook Strait, between the 2 islands of Aotearoa, Maori name of New Zealand. Ocean current may tun up to 1 to 2 knots.
What is not precised on charts, is the current in estuaries or sounds. They are much more unpredictable, because affected by rain and wind away in land.