Cold Wave

A cold wave occurs in a wide range of strong cold air activities during the winter, late fall or early spring in association with severe weather. China’s meteorological department stipulates the criteria for cold waves. North of the Yangtze River, a cold wave is defined when the minimum temperature in a 48-h period has dropped by more than 10 °C due to the intrusion of cold air. In the middle and lower reaches of the Yangtze River, a cold wave occurs when the minimum temperature reaches below 4 °C and is accompanied by winds of grades 5–7 on land and grades 6–8 at sea. In addition, a cold wave occurs if the minimum temperature is below 5 °C. Most cold waves occur during the winter and bring intense cooling and strong winds. They are often accompanied by snow and freezing rain, which have serious impacts on traffic, power transmission, and commercial, industrial and agricultural activities.