Dear Zhu,
Thanks for contacting Top China Travel!
A golden time to travel to Xiamen will be Autumn months including September, October, and November. Sping is a season with little rain, and October is a month mostly influenced by typhoon. The average temperature in this season is about 21.2℃. And I think maybe light fabric like knit is suitable.
Any further request or question, please feel free to contact with us.
Best regards
Lily