There is a little check mark icon that you move with the cursor buttons to allow the data to show on the graph on the bottom left of the display. Move it to the daily rainfall, and you get rainfall for the last 24 hours. and the graph shows the same data. Today, no info on the graph and no data on the line at the bottom of the screen.
And yes that helps. I would have thought mine would say 0.00 as well if the system did not register rain today. But since it rained on and off all day, I was surprised there was just a blank line and not a 0.00