It surpassed the 44.1 degrees Celsius recorded just a day earlier in neighboring Thanh Hoa Province, according to the National Center for Hydro – Meteorological Forecasting.
But from Monday cold air from the north is expected to bring temperatures down.
They are forecast to be 22-27 degrees in Hanoi, according to AccuWeather.
Upland areas such as Sa Pa in Lao Cai Province will have temperatures of 21-23 degrees during the day and 14 degrees at night this week.
Some places in the central region are expected to have rainfall of 20-50 millimeters Monday.
This month average temperatures across the country are forecast to be 0.5-1 degree higher than normal, with the northern and central regions likely to be hot and dry.