You will need two series. Suppose dates are in A2:A100, values to plot in
B2:B100
In C1 use =IF(A1<=TODAY(),B2,NA())
In D1 use =IF(A1TODAY(),B2,NA())
Copy both down their columns
Quickest way is to select all data and make your chart, then delete the line
in the cart for column B (or use CTRL to select A, C and D)

Visit Jon Peltier and look at his 'conditional chart' material
http://peltiertech.com/Excel/Charts/...nalChart1.html

best wishes
--
Bernard Liengme
Microsoft Excel MVP
http://people.stfx.ca/bliengme

"cliffordjf" wrote in message
...
I have a series of values associated with dates; the values in the past
are
fact, the values in the future are estimates. When I graph the data, the
line is all the same color throughout the series. Is there a way to have
the
color of the line change as the dates become past, rather than future....

in other words, the line is black through todays data, but turns to red
from
tomorrow on, then as tomorrows comes, that part of the line turns from red
to
black...

thanx

cjf