'98 Lumina: No Brakes in Rain

When the brakes on my '98 Lumina get wet they become dangerously non-responsive. This has been true ever since I bought the car (almost new). Any suggestions on a fix? Thanks.

Non-responsive in what way? Your ABS should kick in when stopping in rain. You will feel the pedal kicking back a little but will stop in a straight line. If it stops fine in dry weather, the brakes will be fine.
However, if you do not feel comfortable with the situation, take it in to the dealer ( when it is wet ) and let them drive it and try and duplicate the situation to them.