Located just a few degrees south of the Tropic of Capricorn, Hanoi is far enough north to experience four different seasons – winter, spring, summer and fall. Generally, the best time to visit is during spring (March – May) or autumn (September – November), though the climate is increasingly unpredictable, so visitors need to be prepared for anything.
Keep in mind if you plan to visit several regions in Vietnam that climate varies wildly from the north to the central coast to the south, so planning an itinerary that catches the best weather in each region becomes an art in itself.
Also, be warned that like many cities worldwide, Hanoi has been subject to some extreme unexpected weather in recent years, particularly unseasonal floods, so be prepared to wade home to your hotel through knee-deep water.
Winter weather in Hanoi
Between December and February, temperatures drop to around 12°C, and occasionally, as in early 2008, almost down to zero. This makes the city much more temperate than Saigon to the south.
Since there is little in the way of heating in hotels, it’s wise to carry a sweater and a jacket during this season. Rainfall is generally low at this time of year, but can be unpleasant if it is also cold, so pack an umbrella too.
Spring weather in Hanoi
From March to May, rising temperatures, low humidity and rainfall make for a more pleasurable stay, though by May the heat and humidity are on the rise and the monsoon downpours start. This is a good time to go exploring the hills of the north around Sa Pa or Bac Ha, or set off on a road trip to Son La and Dien Bien Phu.
Summer weather in Hanoi
From June to August, Hanoi is hot, humid and wet, so it’s advisable to find a hotel room with air conditioning, not only to keep cool but to shut out battalions of mosquitoes, which proliferate at this time of year. Temperatures hover at around 35°C, though they can hit 40°C on rare occasions. On the plus side, this is also low season, so room rates are lower and the city’s sights are not as crowded with tourists.
Fall and Autumn weather in Hanoi
Between September and November, rainfall and humidity should be tailing off (though it doesn’t always happen), and temperatures should be dropping to a tolerable 20°C-25°C, so this is often the best time to be in Hanoi and North Vietnam. However, there are exceptions, like November 2008, which brought the most serious flooding the city has seen for decades, and almost 100 people lost their lives.