What does it mean that once the Millennium was warm, the autumn was bright and the scenery in the south of the Yangtze River was different?

"The white dew is warm in autumn, and the south scenery of the bright moon is different" comes from the twenty-four solar terms, which expresses the arrival of the white dew solar terms and indicates the beginning of the Mid-Autumn Festival. At this time, the smell of autumn is more and more obvious, the temperature is gradually decreasing, and the cool weather makes people feel comfortable. At the same time, the moon is high, so the scenery in the south of the Yangtze River presents different styles and gives people different feelings.