Hi Ankit
In Karnataka you can visit the following places in December.
1) Mysore
2) Coorg/Chikmagalur
3) Hampi
4) Badami-Aihole-Pattadkal
5) Gokarna-Murudeshwara-Jogfalls
Hey Ankit, Depending on your current location you may choose following options : 1)Delhi -Jaipur, Auli, Rishikesh, Mussourie, Parvati valley,Kullu-Manali, Kedarkantha trek 2)Mumbai -Goa, Wayanand, Allepay, Banglore, Coorg, Munnar, Kumarakom 3)Calcutta — Gangtok, Darjeeling,North Sikkim, Shillong Acc. to my experience i would suggest choose between these three : 1)Jaiselmar
2)Goa
3)Rann of Kutch Hope this would help you.