In southern Florida, and especially in the Florida Keys, there are some very shallow areas that make it very obvious how low low-tide is. I'm stumped to notice that there seems to be significant variations from year to year. For example, an area we call the flats is normalls under six inches of water at low tide. A few years back, it was high and dry at nearly every low tide for seven months. This year is the opposite, and everyone in Southern Florida is talking about unusually high tides. I understand spring tides and neap tides. I understand how large weather patterns out to sea can push water one way or the other for weeks at a time. But I find it hard to imagine anything that would change average high/low tides over periods as long as six months to a year, or that we should have high water years or low water years. No I do not believe it is due to global warming; the changes are much too fast for that. I'm talking about local changes on the scale of perhaps 500 miles in diameter, and I'm talking about annual variations in the average high/low of perhaps 15 cm. El niño like effects on sea level??? The wikipedia article on sea level talks about several reasons for variations but only The Chandler wobble (astronomical) with a 14 month period fits the time scale. No clues in the article about the magnitude of the Chandler wobble's effect on sea level. I'm stumped for an explanation.