With the arrival of the solar term at the beginning of winter, all parts of the country began to accelerate the process of entering winter. At the same time, the impact of the "triple" La Nina event on the climate this winter has attracted much attention. At present, cold air is continuing to affect northern cities, and heating has been put on the agenda in many places. It is estimated that there will be five cold air attacks in November. On the 7th, the China Meteorological Administration held a press conference to introduce that a moderate to strong cold air will affect China from the 10th to the 13th. There will be 4-6 northerly winds in Jianghuai and most of the northern regions. The temperature in most of the central and eastern regions will drop by 4-8 ℃, and some regions will drop by about 10 ℃. It is estimated that there will be five cold air processes affecting China in November. Fang Xiang, deputy director of the National Meteorological Center, said that the cold air that affected China was weak from the 8th to the 10th; From the 11th to the 14th, there will be a moderate to strong cold air that will affect the central and eastern regions of China. The temperature will drop by 4-8 ℃, and some regions will drop by about 10 ℃. Affected by this, the frost line will move further south. On the morning of the 15th, early frost may appear in northern Henan and parts of Shandong. "The stronger cold air will mainly affect northern agricultural areas this time, increase the cost of cold protection and warmth preservation for facility agriculture and animal husbandry, and have less impact on winter wheat that is still in the seedling stage." Fang Xiang suggested that before the frost comes, apple, pear, jujube and other production areas should be harvested in time and the orchard should take cold prevention measures. The greenhouses and livestock sheds in the north should also be strengthened and kept warm to prevent the impact of low temperature. The La Nina event will last until the winter of 2022/2023. The latest monitoring shows that the La Nina event in the equatorial Middle East Pacific has continued since October. It is expected that the La Nina event will last until the winter of 2022/2023. Xiao Chan, deputy director of the National Climate Center, introduced that this event is the three La Nina events that have developed again from the summer of 2020 to the spring of 2021, from the autumn of 2021 to the early summer of 2022, and from the autumn of 2022 in the following three years since the equatorial Middle East Pacific Ocean rapidly turned cold in the spring of 2020. Therefore, it is also called the "triple" La Nina event. Xiao Chan said that the La Ni ñ a event is only one of the underlying forcing factors that affect China's autumn and winter climate, so there is no need to "talk about La Ni ñ a becoming pale". China's winter climate is also affected by Arctic sea ice, Eurasian snow cover and other factors, while the natural variability within the atmospheric system also plays an important role. According to the prediction of the meteorological department, the cold air intensity that affects China this winter is generally weak. Except the temperature in the east and west of Inner Mongolia, the north of northeast, most of south China, southeast of southwest, and middle and east of northwest is lower than that in the same period of the year, the temperature in other parts of the country is close to or higher than that in the same period of the year. Temperature conditions or influences heating ahead November is the time when heating starts in many places in the north, and Lhasa, Yanji and other cities start heating one after another. According to the Beijing Municipal Commission of Urban Management, Beijing officially started the trial operation of the heating system on November 7. Fang Xiang said that various regions have formulated relevant standards on whether to heat in advance, and generally refer to the daily average temperature of five consecutive days. Taking Beijing as an example, it is stipulated that the daily average temperature for five consecutive days is 5 ℃ or below, or in case of strong snowfall and other weather that may have an important impact on residents' warmth