is it possible to visit ChangBai Mountain January, doing a day trip back and forth from Jilin city?

Yes, you need to stay overnight since you will spend a lot of time on the way. You can take a high speed train from JL Railway Station to Antu West Station and it takes about 90 minutes. After that, take a taxi to Antu Bus Station and take a bus from there to Erdai River Town, which will take around 3 hours. Then take a tourist bus directly to the scenic area.

Hi Lily,

Is it too cold to visit in Jan?
Thank you.

Yes, that will be pretty cold and if you want to go in January, preparing enough warm clothes. By the way, generally you can only see the overview of Tianchi Lake from July to September.