I would say... Nainital.... coz. The weather of nainital in January will be very fine for exploring the places. ... doing small treks. do visit the Rajbhawan , golf course,naina peek,tiffintop,snowview and enjoy the trolley ride too to enjoy the magnificent view of naini lake.
Hey Sayani, The state of Uttarakhand comprises of many picturesque destinations that you should visit during your holidays. Some of them are: > Auli - best skiing destination in India
> Dehradun/Mussoorie - most popular getaways from Delhi. > Chopta - an offbeat destination with much to offer!
> Binsar - amazing for treks.
> Pithoragarh - scenic town with adventure sports. Do check out the many guides on Uttarakhand available on Tripoto so you can make an informed destination regarding which destinations to visit: https://www.tripoto.com/travel-guide/uttarakhand