2. Initial accommodation: 2021July1day-2021July 20th, *** 10; Zhongfu: 2021July 21-2021August 9, ***20 days; Terminal: 2021August10-2021August 19, *** 10 days.

3. The humidity of the ground surface becomes higher after falling, and the heat absorbed every day is more, but the heat emitted is less, and the heat on the ground is accumulated. So it's getting hotter every day, entering the dog days, and the accumulated heat on the ground reaches its peak, and the weather is the hottest. In addition, there is much rain in summer, the air humidity is high, and the heat capacity of water is much greater than that of dry air, which is also an important reason for the sultry weather. The subtropical high intensified in July and August. Under the control of the subtropical high, the descending airflow inside the high makes the weather clear and cloudy, which is beneficial to the sunshine, the ground radiation heats up and the weather is hotter.