Temperatures in Hanoi dropped to 13 degrees Celsius on Nov. 19 morning, about 6–7 degrees lower than the previous day. It was cold with occasional light rain, yet many people still kept up their habit of exercising around Hoan Kiem Lake.
Across all 15 northern provinces and cities, temperatures in the morning were below 15 degrees Celsius. Mount Mau Son in Lang Son, perched 1,500 meters above sea level, recorded just over 3 degrees. The drop was caused by a strong mass of cold air sweeping into the northern region before moving down toward central Vietnam.