I'm going up to Zhongdian for about 5 weeks and i've heard that it gets cold even in summer time.

Where can I buy a good fleece/waterproof jacket/walking boots etc.

Thanks

There is a camping store on Wen Hua Xiang (near Mandarin Books), that has western quality goods at almost-western prices. Apparently you can bargain a bit in there, too.

If price is a consideration then try the 2nd hand market across from the big bus station at huantapour.