It starts at 5pm. They do not allow guest passes this year. However if your guest passes are already in the zoo (prior to 5pm) you can stay for the lights.
Evening
Christmas lights are 5 - 9 pm. Highly recommend downloading the Riverbanks Zoo app to your phone. The zoo does an awesome job with both Boo at the Zoo and lights before Christmas. We've been going for years and just love it!!!!
My group was only there for an hour
Thanks! Your answer is awaiting moderation.