When can you see dew on the grass in the Millennium?

When the temperature drops below the dew point, excess water vapor will condense into water droplets. On a clear and windless night, when the temperature of grass leaves on the ground or near the ground drops below the dew point, crystal dew will appear on the grass.

Millennium is one of the 24 solar terms of the lunar calendar. When the sun reaches 165 degrees, it is called the Millennium solar term. Millennium is the third solar term in autumn, marking the end of Qiu Meng and the beginning of Mid-Autumn Festival. Dew is water droplets formed by condensation of water vapor on the ground or near-earth objects due to temperature drop. So the Millennium actually indicates that the weather is getting cold. At this time, people will obviously feel that the hot summer has passed and the cool autumn has arrived.