The ceremony at Jack London Square in Oakland will take place from noon to 7 p.m., according to event officials. Oakland Mayor Ron Dellums is expected to flip the switch at 6 p.m. of the 4,500 energy efficient lights covering the 55-foot tall tree.
Prior to the tree lighting, choirs from throughout the Bay Area will compete in the KBLX 102.9 High School Choir Competition, followed by other local bands.
Ghiradelli Square's ceremony in San Francisco begins at 1:30 p.m. with the tree-lighting portion at 5:30 p.m., event officials said.
The lighting of the 35-foot tall tree will be led by television station KPIX weather anchor Roberta Gonzales.