Why does Linzhou bloom in winter and freeze in summer?

Taiji Mountain is located in Taohua Ancient Village, Shibanyan Township, Linzhou City, and Yang's home is next to Taiji Mountain. At that time, Taiji Mountain was not called Taiji Mountain, because it was frozen in summer and steamed in winter, and was called Yin and Yang Mountain by the villagers. The most obvious phenomenon of freezing and steaming is the ice cave. When Yang was a child, his family was very poor. Every winter, he rakes leaves on the mountains of Yin and Yang for cooking pots and composting. The coldest time on the mountain is MINUS 14.5 degrees Celsius. Whenever Yang can't stand the cold, he goes to the ice cave to keep warm. The ice cave is 10-20 meters deep (now it has collapsed, leaving only a part of the hole), which is completely another world. The underground is like an air conditioner, steaming out constantly, so hot that you need to take off your thick cotton-padded clothes after going in. After it snowed, other places were covered with snow, but there was no snow within a few meters near the hole. Yang couldn't figure out why there was hot air in the ice cave in winter, and the colder it was, the more hot air it was. After the spring of the following year, with the warming of the weather, the hot air disappeared and the ice caves began to freeze, especially in June, July and August. The hotter the weather, the bigger the ice and icicles hanging upside down in the ice cave. Once upon a time, there was a family named Li who lived in the mountains. In winter, they need a gourd to get water at the foot of the mountain. In summer, they go directly to the ice cave to get icicles, which are melted and used as water to drink. Villagers collect herbs or work in the mountains, and when they are thirsty, they go to the ice cave to eat icicles as ice cream. Strong curiosity drove Yang to find out. He climbed every corner of Yinshan Mountain and found thousands of small holes with the same phenomenon. Some of these holes are only the size of fists, but they risk air conditioning in summer and heating in winter. In summer, they uncovered the stone at the mouth of the cave, and there were pieces of ice bumps hidden under it. This abnormal phenomenon makes Yinyang Mountain a unique landscape: after the summer rainstorm, the whole mountain is foggy and spectacular, but there is no fog on the adjacent mountains; On a clear and windless day, the leaves and weeds under the trees at the foot of the mountain have been shaking, and many butterflies on the mountain dare not fly in the grass because they are easily frozen. There are birch and sumac trees that only grow in cold areas such as northeast China and Russian.