Windows are condensating on the inside

[George P.]

My 20+ y.o. Anderson windows condensate on the inside when: 1) the shades are down for the night, and 2) the temperature difference between the room and the outside is significant (68F inside and 35F or below outside). But after when I pull up the shades in the morning, the moisture on the lower third of the window evaporates after a couple of hours.
Is this normal or my windows need replacing?
Thank you

P.S. I don't have any other issues with these windows.