Hi, I want to visit Jiuzhaigou and Zhangjiajie.

1. For Jiuzhaigou, September to November is regarded as the best period for sightseeing.
The temperature will be 50 F to 65 F during that period of time. It will have many sunny and cloudy days. You can bring jackets, T-shirts and pants.

2. For Zhangjiajie, September to October is highly recommended. It will be 60 F to 75 F. The climate will be cool and comfortable. Light jacket, T-shirts and jeans are enough.