Radio Clyde's Gina McKie will host the event in Carluke which kicks off at 3pm on Friday, November 15, with the switch-on at 6pm.
Meanwhile, Real Radio's Paul Harper will oversee celebrations in Lanark on Saturday, November 16.
The event will begin at 3pm, with the lights switch-on scheduled for just before 5pm.
Both spectaculars will feature a Christmas Chartbusters Review Show, featuring popular festive hits.
South Lanarkshire Provost Eileen Logan will also be on stage for the countdown.
Chair of South Lanarkshire Council's Enterprise Services Committee, Councillor Chris Thompson, said: "I hope as many people as possible will come and help us celebrate."