Don’t show the current, running day in the dashboard.
Instead only show days that are fully completed.
Right now, if you go to the dashboard in the morning, you see a sharp decline.
The dashboard displays complete days but before the day is over.
So if you got 1MB in the morning, it will show you 1MB for the current day.
That is probably a sharp decline form the 1000MB you got in the last day.
Of course it would also be possible to change the x-axis instead to match the current time instead of full days, but I think just leaving out the running day is probably a simpler solution.
There was a post some years ago about the same topic.
One is to to show projected value for the current day: what would it be if load continues, with different curve style. E.g. dashed.
Better yet — just make the last x-coordinate current time. Instead of the future. The meaning of the graph is essentially data rate: integral of the curve gives you total traffic. Today the plot uses whole dates to average over. By having fractional last date, you can show actual data rate by now. I think it’s much more accurate and useful than zero or omitting the last day altogether. In fact, I’d argue that last value is the most important one.