Time to trim the trees Temperatures may be shifting back and forth between summer and fall, but winter can't be far away judging by this harbinger. Dean Brimley is starting the annual ritual of stringing lights on Temple Square, which still has flowers in bloom despite the yuletide preparations. About 250,000 lights will be used to trim all the trees in their Christmas finery. The process, which takes weeks, will be finished and the switch pulled the day after Thanksgiving.