What's the weather like in Xiamen in May?

It won't be very hot, but it will rain with a cold rhythm.

I suggest you take short sleeves, long sleeves or a thin coat. It's really cold when it rains, and it's windy at night, so it's cold when it blows.

I suggest you install a local tour APP directly on your mobile phone. There is one in Gulangyu, Xiamen, which is used for dating and asking for help. You can go up and post to ask about the weather, wear an inn and so on. Or you can find a little friend to play with. People are very popular.