What's the weather like in Guangzhou during the New Year? How much to wear?

Generally, when Guangzhou is coldest in winter, you only need to wear a sweater and a thicker coat. Wearing a scarf outside for a long time will be warmer. However, the weather in Guangzhou is changeable and may get hot this year. However, the temperature may be higher during the day, and 1 month rarely exceeds 20 degrees. You don't feel hot without a sweater, but it will count when you enter the house, because all shopping malls have heating at 20 degrees. It was said upstairs that there was 3 1 degree in Guangzhou last year, but in all my memories of more than 20 years from birth to now, there is 3 1 degree, which is the highest temperature in my impression, that is, 20 degrees, and 3 1 degree is too hot to wear clothes.