The origin of autumn tiger?

Autumn Tiger refers to the short-term hot weather after neutral autumn in 24 solar terms, which is as overbearing as a tiger, so people call this period "autumn tiger". It usually occurs between August and September, and the duration of autumn tiger varies from year to year, usually lasting for half a month to two months.

There are also twenty-four autumn tigers among the people, which means that if it doesn't rain on the day of beginning of autumn every year, the weather will be very hot for the twenty-four days after beginning of autumn, and these twenty-four days are called twenty-four autumn tigers; But if it rains in beginning of autumn that day, even if it is only a light rain, it is "suitable for autumn". An autumn rain and a cold also mean that the weather will be more and more refreshing and pleasant after autumn.