When does autumn tiger mean?

Autumn tiger is a common name for the short-term high temperature weather that reappears after autumn. It usually happens at the turn of August and September and lasts about 7- 15 days. The reason for the formation of autumn tiger is that the western Pacific subtropical high that controls China gradually moves southward in autumn, but moves northward. Under the control of this high pressure, it turned cloudy and sunny locally, with strong solar radiation and rising temperature. This regenerative weather is called "old woman summer" weather in Europe and "Indian summer" weather in North America.