At least a month, I like to scan through and see when the next daytime low tide is coming and your graph is the best for that I've seen yet.
I aim to please I also plan to restore zooming and some plot interactivity on mobile. At the moment the graphs are static on small screens, and interactive on wide screens. I found that it was hard to scroll on mobile because touching the graph caused zooming rather than page scroll, but this can be modified. And also perhaps some minor gridlines on mobile
Could also create a search field for finding the next day with tides below a certain threshold. I do find that day time tides are higher in the winter months, possibly just due to less hours of daylight, but the low tide in Winter always seems to happen after midnight and before dawn rather than during the day.