Bailu Bailu is the first solar term in September. Dew is water droplets formed by condensation of water vapor on the ground or near-earth objects due to lowering of temperature. Therefore, white dew actually means that the weather has turned cooler. At this time, people will clearly feel that the hot summer is over and the cool autumn has arrived. Because although the temperature during the day is still in the 30s, it drops to the 20s after night, and the temperature difference between the two is more than ten degrees. Yang Qi reaches its peak at the summer solstice, when the extremes of things must reverse, Yin Qi also rises at this time. When it comes to the White Dew, the Yin Qi gradually increases, and the dew in the morning thickens and condenses into a layer of white water droplets, so it is called White Dew. As the saying goes: "It's eighteen days after the summer heat, and the white dew comes, so don't expose your body." These two sentences mean that when the summer heat is still hot, you must take a bath with a basin of water every day. After eighteen days, when the white dew comes, don't be naked. , to avoid catching cold. There is also a saying: "The dew is white and the rice is beautiful at the autumnal equinox." This means that if there is dew before and after the white dew, the late rice will have a good harvest.