Travel Jiuzhaigou in early July, what should I Wear?

I visit Jiuzhaigou this July, probably in early July and was recommended to bring a thick sweater, for the weather differ dramatically between daytime and night. Do I need to bring a thick sweater? or what should I wear. please help me.

it's usually a bit cold in early morning and at night time so you may consider to bring warm clothes, but so far as I know, a relatively thick coat is enough.

it will be very cold in the morning. you'd better prepare a thick coat.

Temperature can plummet to as low as 10 Centigrade at night and in early morning. Warm clothes are needed. somebody travel there last may, it stangly snowed at that time.