Nov 9, 2014 - 10:36 AM
Hi Azher, welcome to MySwissAlps!
I wouldn't say Interlaken is the best place to visit in Switzerland. It's not a beautiful town, it's rather a practical base because of its convenient train connections, and many shops, hotels and restaurants. See here for information please: www.myswissalps.com/interlaken.
All of Switzerland will be chilly or cold in December, but one can only know 2 days ahead. Also it depends on where you will be based: it will be warmer in a valley (e.g. Interlaken) and colder in the mountains. If you like to be surrounded by snow you chances are better in the mountains.
More towns can be found here: www.myswissalps.com/wheretogo/towns (be sure to take a look at Lucerne too).