I am travelling to Jiuzhaigou, Huanglong and Mt.Emei on 16Sep15 to 20Sep15.

The weather is changeable in Jiuzhaigou and Huanglong. Based on the previous weather records, it is warm then and the temp may range from 15C/59F to 26C/79F. Both cloudy and rainy days would happen. In the lake areas of the valley and the top of the Huanglong, it is much cooler. I suggest you prepare short-sleeved and short-sleeved shirt, light jacket and pants as well as simple rain gear.

It is warmer at the foot of Mt. Emei, but cold on the mountaintop, where you even need to wear downjacket. Don't worry! The downjacket rental is available at sight. In addition, the past weather shows that it may frequently rain. Do check the weather forecast before leaving.