The summer season in Hanoi is generally taken to run from May to September, the three warmest months being June, July, and August. It is here that temperatures reach anywhere between 35-38°C (95-100°F) under extreme humidity.Climate also varies by a few degrees each year from year to year.
Summer in Hanoi normally takes place between June and August. The weather conditions of Hanoi have some difference in different regions and times of the year. But by and large, the high temperatures and long hours of sunshine on a summer day offer very good conditions for outdoor activities such as hiking, sightseeing walks, and swimming.
June and July are the leading months with warm weather; daily average highs reach 28-31°C (79-88°F) and daily average lows 20-25°C (68-77°F). Rain falls a little, in the form of showers or thunderstorms, but of an intensity not high enough to interrupt daily routines.
August is slightly cooler yet, with daily average temperatures falling within the range of 24-28°C (75-82°F), although high humidity, with its accompanying solar radiation, will remain. Should your visit be in August, do not forget to include light clothing and comfortable shoes for outdoor activities along with sunscreen protection for skin against ultraviolet rays.
In Hanoi, Vietnam's capital city, summer usually spans May through August. The weather is, in that period, hot and sticky, generally ranging from 30 to 35°C (86 to 95°F) or even more. It is also the rainy season, so expect rain showers, rather frequent, particularly in the afternoon.