how far is it from nanning to kunming

It is around 800 to 850km between the two places.

I will be going to NN this Chinese new year for 5 weeks.Between lijiang and Kunming which is better to visit? I am planning for a week. Is there any Gym in NN beside in hotels.Is there any good apartments I can rent for a month? What is the weather like In Jan to Mar?Looking forward for any information given.
Thanking you in advance.
Philips

In my opinion, the both of the two places are worth visiting. I think you can spend about two days in KM and then the rest of the days in Lijiang.
Which hotel do you live in NN? As far as I know, most of the hotels have their own gyms, so I think you can check it in your hotel first.
Near local Minzu Avenue, there are some communities, so I think you can live there. The communities include Xinhu and Lantian Communities.
It is not cold during Jan in NN and the average temperature is around 7 to 15C during that time and in March, the temperature is around 20 to 25C.