[Cold air comes online over the weekend, and temperatures drop by 10°C in many places in the north] September 17th, for three days from today (September 17th to 19th), the temperature will continue to be high in most parts of the central and eastern regions, with the highest temperature remaining at around 30°C, and the afternoon heat will continue to be online. However, the temperature difference between day and night is large in the north, and in some areas it will exceed 15°C, making it feel like two seasons have passed in one day. Over the weekend, the eastern part of Northwest China, northern North China, Northeast China and other areas will be affected by cold air and the temperature will fluctuate. However, the impact of the cold air is limited, and the heat in the south will continue until the end of the month. (China weather)