As time flows and years change, let's learn about the 24 solar terms through the phenological guide. Today (September 7th), we welcome the third solar term of autumn—White Dew. At this time, the summer monsoon gradually weakens, cold air activity becomes more frequent, and the summer heat dissipates and autumn deepens in many parts of the north. In many parts of the south, the summer heat still lingers, but the temperature difference between day and night is quietly widening, and dew is already condensing on the grass and trees in the early morning. China Weather Network, in conjunction with the Key Open Laboratory of the 24 Solar Terms of the China Meteorological Administration, has released a national map of the arrival of autumn coolness during the White Dew solar term, showing where the coolness of autumn arrives first.

During the White Dew season, the summer heat dissipates and a cool breeze arises, as the world quietly transitions from summer to autumn. Meteorologist Song Yingjie, in his book "Knowing the Seasons in the Forbidden City," describes the characteristics of this season as follows: "In the south, it is still summer; in the north, autumn is gradually approaching. The golden winds of the south dispel the heat, and the scorching heat gradually recedes; in the north, the dew brings coolness, and early autumn has arrived."

A map showing the arrival of cool weather during the White Dew season reveals that, typically during this period, the average minimum temperature in Heilongjiang, Jilin, Liaoning, northern Hebei, Shanxi, northern Shaanxi, Inner Mongolia, Ningxia, Gansu, Qinghai, Xinjiang, Tibet, and western Sichuan is already below 15℃, with noticeable coolness in the mornings and evenings. Stepping outside in the early morning, a chill is immediately felt, vividly illustrating the old saying, "The nights of White Dew and Autumn Equinox grow cooler with each passing night."

The first sign of White Dew: Wild geese arrive.

Birds are very sensitive to seasonal changes. When the autumn winds rise, wild geese fly south. During the first phase of the White Dew solar term, wild geese set off from their summering grounds in the north and migrate south, passing through the middle and lower reaches of the Yellow River, a phenomenon the ancients called "the arrival of wild geese." At this time, the geese fly in V-formations or straight lines, slowly heading south in the clear autumn sky, a clear signal that autumn is coming.

The second phase of White Dew: Swallows return

During the second phase of the White Dew solar term, swallows begin their collective southward migration to warmer regions for the winter. Swallows, generally referred to as "black birds," were considered by the ancients to be southern birds that migrate north in spring when flowers bloom and return south in early autumn. Unlike the leisurely formation of wild geese, the swallows' migration is more discreet, seemingly disappearing "overnight," leaving only empty mud nests under the eaves to signal the arrival of autumn.

The Three Phases of White Dew: Birds Store Food

The character “羞” is the same as “馐”, and “养羞” means to store food. During the White Dew season, migratory birds fly south one after another, and some birds begin to store food in preparation for the coming winter. With the changing seasons, all things in nature gradually show phenological changes from abundance to harvest.

Beyond phenology, the White Dew season also brings many seasonal customs. In Hunan and the Jiangnan region, there is a tradition of brewing "White Dew Rice Wine," which is warm and served to guests. In Fujian and other places, there is a custom of eating longan, which is large and sweet at this time and is believed to be good for health. In the Nanjing area, there is also a custom of drinking "White Dew Tea," which is sweet, mellow and fragrant. There is a saying among the people: "Spring tea is bitter, summer tea is astringent, for the best taste, choose autumn White Dew."

"A gentle breeze sweeps across the land, and the white dew has suddenly condensed." With the arrival of White Dew, the summer heat gradually recedes, and a cool breeze begins to rise. In many places, it marks the most comfortable time of year. Chrysanthemums bloom yellow, and autumn leaves turn red. Why not spend time with family or a few close friends, stepping outdoors into the autumnal landscape to watch the clouds drift by, listen to the wind rustling through the treetops, and appreciate the tranquility and vastness of autumn with every step? (Source: China Weather Network)