For the past two days, the border commune of Na Ngoi, formerly part of Ky Son district, has experienced temperatures below 0 degrees Celsius, leading to frost on vegetation and rooftops.

With temperatures dropping below 0 degrees Celsius, Phu Sa Phin peak in Lao Cai and Ngu Chi Son peak in Lai Chau are covered in thick frost, which has persisted from morning until afternoon.