Ok, fine for an XY line graph. What about: plot flow as line and same graph
Rain as bar graph. You will get one big bar for the entire day with the rain
totaled.

"David Biddulph" wrote:

Sorry, I don't see your difficulty. Combine date and time in one column, &
use that as the X values for your XY chart.
--
David Biddulph

"mjwedeking" wrote in message
...
How can you plot data that is less than daily? I typically create charts
of
data that has hourly or even 15 minute time steps. Excel will sum all the
values for the day and just plot daily data, or monthly, or yearly.

Sample Data:
A B C
Date Time Flow(mgd) Rain(in)
2/13/2007 1:00 1.2 0
2/13/2007 2:00 1.3 0.1
2/13/2007 3:00 1.5 0.2
2/13/2007 4:00 1.1 0