How thick should I wear to go to Dalian tomorrow?

The weather forecast in Dalian says it will rain tomorrow, with 11~16 degrees Celsius. It's said that the weather will change again in Dalian. If there is sunshine in Dalian during the day, the temperature will be very high, and it won't be very cold if you wear short sleeves. But if it rains, the temperature will be very low. It is recommended to wear long sleeves, and bring a short-sleeved dress if you are afraid of heat. Anyway, short-sleeved clothes are very small.