Not an exact method of calculating by any means, but generally speaking, if you know the time of a given low tide you can estimate that the corresponding low the following day will be about an hour later.
Each day there’s a “low low” and “high low” tide level, and also a “high high” and a “low high” tide level.
Tides are lowest and highest at new and full moons; during quarter moons they are not as extreme.
The lowest tide of winter will usually be at approximately midnight on the night of the full moon closest to the Winter Solstice, and the lowest tide of summer will be at approximately noon on the day of the full moon closest the Summer Solstice. This is purely coincidental for Seattle, as it happens; the explanation I was given by an oceanographer for why it happens that way was incredibly complicated and I’ve forgotten most of it, but I think it’s pretty cool that it works out that way.
