I heard yesterday that it was the Millennium. What exactly does the Millennium mean?

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.