In the traditional Chinese calendar, the year unfolds through 24 solar terms, with "Liqiu," the 13th solar term, heralding the beginning of autumn. This year, this transition takes place on August 8.

Despite officially marking the arrival of autumn, this period does not always signal a farewell to the lingering summer heat. In reality, as the inaugural solar term of autumn, Liqiu coincides with the "Sanfu" period or dog days – the annual peak of heat and humidity.

"Autumn Tiger" is an intriguing and distinctive meteorological phenomenon in Chinese folklore that refers to a short period of re-intensified hot weather following the start of autumn. It typically occurs from late August to early September and lasts for between seven to 15 days.

The formation of the Autumn Tiger stems from the evolving patterns of the Western Pacific Subtropical High – a prominent high-pressure system hovering over the Pacific. During autumn, this system gradually shifts southward while retaining some northward influence. These dynamics yield clear skies, minimal clouds, intensified sunlight and rising temperatures. In Europe, it's often referred to as an "Old Wives' summer," while in North America it's known as an "Indian summer."

Due to China's vast geographical expanse, the manifestations of the Autumn Tiger vary from region to region. For example, the appearance of the Autumn Tiger in southern China is delayed in comparison to its arrival in the Yangtze River Basin, where it usually lags by two to four solar terms.

Additionally, the duration of the Autumn Tiger each year can vastly differ, lasting from between two weeks to two months. Sometimes, the Autumn Tiger may recede for a while and then unexpectedly return. Although the temperatures during the Autumn Tiger period are higher overall, the air is relatively dry, sunlight is abundant, and the early morning and evening hours are not overly hot.

In China, the Autumn Tiger is further classified into "male" and "female" categories. This distinction is based on the date of Liqiu. According to the traditional Chinese calendar, if the date of Liqiu is an odd number, it's referred to as the "male" Autumn Tiger; whereas if it's an even number, it's called the "female" Autumn Tiger.

This folk tradition adds an element of mystery and amusement, making the Autumn Tiger a unique and captivating topic among Chinese people.