When can Shantou wear short sleeves? The weather is still so cold.

It's still very cold because it's the third month of the lunar calendar, and Grain Rain is the day after tomorrow. But it's still quite hot at noon now. I think we should wait until the end of May or the beginning of June, because it is almost the summer solstice of the lunar calendar and the weather will be very hot. It used to be very hot around May Day, but last year was a leap month, so the lunar calendar went slowly.