The temperature in spring and autumn is pleasant, so you can wear light clothes, but it's a little cold in the morning and evening. It is recommended to bring a thin coat. When the temperature is high in summer, you can wear short-sleeved shirts, shorts and other summer clothes. The temperature is low in winter, so you need to wear heavy down jackets and sweaters to keep warm.
Jiuzhaigou has a high terrain, and the weather in mountainous areas is changeable. There will be sudden cooling or rain, so take rain-proof and cold-proof clothes at the right time.