Core Points - A strong cold air mass is expected to impact China from October 16 to 21, leading to the lowest temperatures of the second half of the year in most regions [1][3] - Beijing is forecasted to experience a significant drop in temperature, with nighttime temperatures falling to single digits starting from October 17, and potentially reaching around 2°C on the night of October 19 [1][3] - This cold air mass is considered the strongest of the second half of the year, with a prolonged impact and significant temperature drops [5] Summary by Sections Weather Forecast - The cold air mass is expected to lead to continuous average daily temperatures below 10°C in Beijing from October 18 to 24, indicating an early onset of winter [3] - The average winter onset date for Beijing is typically October 31, based on historical data from 1991 to 2020 [3] Temperature Impact - Northern regions will experience persistently low temperatures, with areas like North China and eastern Huanghuai expected to have average temperatures below 10°C for five consecutive days starting October 18 [5] - Initial frost is anticipated in northern China, including regions like Liaoning [5] Weather Warnings - Beijing's meteorological authority has issued blue alerts for cold waves and strong winds, warning of temperature drops of around 8°C and nighttime lows of about 4°C in plain areas [5] - Frost warnings have been issued for several districts, indicating potential agricultural impacts due to low temperatures [5] Health Advisory - The Beijing Center for Disease Control advises the public to take precautions against the cold, including wearing appropriate clothing and maintaining good hygiene practices to prevent respiratory illnesses during the flu season [6]