![]() ![]() High tides, depending on location and local geography, can be really high – the record these days is in Canada's Bay of Fundy, where the difference between low and high tide can be up to fifty feet. Where the change between high tide and low tide is at its smallest a Neap Tide has occurred. If the Sun, Earth, and Moon's position form a 90º angle then you get a neap tide ("neap" is from an Anglo-Saxon root, meaning "weak") which is unusually low. The graph below shows the tide heights for Iken Cliffs over the next seven days. ![]() If the Sun and Moon are both in alignment then there's an additive effect from the gravitational fields of both, and you get an unusually high tide called a spring tide (the term is derived from "springing up" and doesn't have anything to do with the season). Counterintuitively, you get a tidal bulge not just directly under the Moon, but on the opposite side of the planet as well, which means two high tides, and two low tides, per day. As the Moon orbits the Earth, its gravity pulls the ocean water beneath it into a tidal bulge and as any given location – hapless lower Manhattan, for instance, during Superstorm Sandy – rotates through the tidal bulge, it experiences a high tide. Astronomy info from the Old Farmers Almanacincluding rise and set times for the Moon, Sun, and planets, full Moon names and dates, Moon phases, eclipse dates, meteor showers, and more.
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