Fortunately the maximum variation is only about two inches. If the variation was 10 or 12 feet as it is at most places along the Maine coast, Chicago would be a different city. However, the lake level also varies a few feet when the water, driven by strong winds, pulls away from one shore and piles up against the other.
Lunar tides are a curious phenomenon.
In general, the ebb and flow are synchronized with the rising and the setting of the moon, so that a high tide occurs twice every 24 hours and 51 minutes. The moon exerts a strong pull upon the waters that cover most of the earth's surface. Its path around the earth being an ellipse, rather than a circle, produces a monthly variation in the tides. Because that path is not in the same direction as the earth's path around the sun, there is also a daily variation in the tides. Using mathematical formulae, the exact times at which the high and low tides will occur each day at any given location can be predicted.