This was 1.7 lower than the previous day, forcing local residents and tourists to wear warm clothes when going out.
Shops selling clothes and headwear saw a surge in buyers while walking trails such as Sapa-Ta Van and Sapa-Lao Chai attracted large numbers of visitors.
According to weather forecasters, a weakening convergence zone and low-pressure trough had led to fewer clouds at night, then causing heat on the ground to radiate quickly and reduce temperatures steeply.
Earlier on September 4, the temperature in Sapa plunged to 12.9C, the lowest in the first ten days of September since 1957.
Director of the Lao Cai Meteorological Station Luu Minh Hai said the abrupt temperature reduction in mid-August is an abnormal phenomenon, signifying that this year’s winter will come earlier and be colder than normal.
