where are the best places to visit in mid Dec? I will be there for 12 days.

Oh, 12 days are long enough to visit many parts in the province and this is an itinerary for reference:
Day1: Qiongzhu Temple, Stone Forest
Day2: Erhai Lake Park, Three Pagoda Temple, Dali Old Town
Day3: Bai Minority Traditional Houses, Square Street of Lijiang Old Town
Day4: Baisha Village, Lijiang Mural, the Old Town of Shuhe, Tea-Horse Road Musuem
Day5: Tiger Leaping Gorge, Stone Drum Town
Day6: Songzanlin Temple, Bitahai Lake
Day7: Golden Temple, Daguan Park, Flowers and Birds Market
Day8: Manfeilong Pagoda, Manting Park, Octagonal Pavilion
Day9: Xishuangbanna Nationality Culture Park, Wild Elephant Valley
Day10: Single-Tree Forest, Manfeilong Buddhist Pagoda
Day11: Olive Dam, Xishuangbanna Tropical plant Research Insititute
Day12: return back to Kunming