Measuring in weeks is not good enough, because too terrestrial. At least should mark on figures Moon phases (at least extremes), because, all life on Earth synchronized on tides, because water level changed not on shore only, but underground water also affected by tides.
And with knowing of Moon phases, you are armed and powerful.
Considering Moon phases, you could make the most from most fruitful part of Moon circle (when water level near top and raising), and avoid hassles from transitional part (from raise to decrease, especially, when combined with eclipses, which themselves could multiply tide near to twice), and better use decreasing part of circle.
Plus, good thing, to add Solar magnetic activity circles, which also relatively easy to calculate.
Yes, must admit, for most young people, Solar magnetic activity is mostly unnoticeable, but extreme parts of these, could even affect modern technology, for example, it could create potentials in railroads and in power lines, or even in large buildings, not too much, just about ten volts, but enough for wrong activation of some mechanisms or to trigger safety systems and to turn off part of railroad or power grid.
Also, these harmful potentials could affect copper communication lines.
And sure, Solar magnetic activity affect Earth weather, which is not so much important for terrestrial civilizations, but could very hard affect sea transport.