condensation from central air conditioner.

Hi all, For some time now I have been noticing moisture condensation on the surface of the outgoing cold ducts to the point of it wetting the insulation covering some of the ducts and wetting the floor. I have never noticed this condition before and would appreciate some ideas why this is forming now. We have had some 90 degree weather lasting for about two week a week ago, It is in the 80 degrees now.Thanks for any ideas. snipped-for-privacy@optonline.net