Will it be cold to wear shorts and sandals in Xiamen on May 5th?

It won't be cold, but if it rains for several days, it may be a little cold, but it's not cold. Take only a thin long sleeve as a backup. There is basically no problem with shorts and short sleeves during the day, because I am playing computer with shorts and short sleeves now, and I am replying to you. So it was already very hot on May 5th. Unless there is a strong wind and heavy rain, we should pay attention to the weather forecast when we get close, mainly whether it rains or not.