Puankha is another district close to Thimphu and a popular destination for tourists. It's a beautiful valley, without much modern development. So you will see most of the culture is intact. It ahd also served as a capital until 1950s when the Third King of Bhutan Jigme Dorji Wangchuck has shifted to Thimphu.
Punakha valley has a pleasant climate with warm winters and hot summers. It is located at an average elevation of 1200 m above sea level. Owing to the favorable climatic conditions, rice has become the main cash crop cultivated in the region.
It's also a historic place in Bhutan which served as the capital till 1952 and still serves as the winter capital for the monastic body.
There are a lot of places that you may like to visit, hike or opt for an adventure such as river rafting.