The best time to visit Vietnam: north, central and south

Vietnam stretches a long way from north to south, and its weather changes along the way. The north has a real winter, the central coast gets its rain in autumn, and the south has a simple wet and dry season. A month that is perfect in one region can be the worst in another, which is why the best time to visit Vietnam depends on where you spend most of your days.

That matters because most trips cover all three regions, usually from Hanoi down to Ho Chi Minh City or the other way. The seasonal descriptions follow the Vietnam National Authority of Tourism, and the storm and flood notes follow the UK Foreign Office. Temperatures are left out unless an official page gives one.

The north, including Hanoi, Ha Long Bay and Sapa, is described by the tourism board as cool to cold, misty and cloudy from December to March, warm to hot with clear skies from April to June, hot, humid and stormy from June to August, and mild with clear skies from September to November. The central coast, from Hue through Da Nang to Hoi An, is warm to hot and sunny from about February or March to August and rainy and cooler from about September, with Hue's wet spell running to February.

The south, with Ho Chi Minh City and the Mekong Delta, has consistent temperatures year-round. The tourism board gives clear, hot and sunny skies from December to April and sporadic rain, hot and humid conditions from May to November. So for a single route through the whole country, the overlap of good weather is March to May, which is exactly the window the tourism board names as the best weather countrywide.

The crowd and price columns are tendencies, not published figures. Check your dates against Tet and the fixed public holidays below before you book.

Start with the one place you cannot compromise on, then choose the month. The table gives a best window for each common goal and the months that cost you the most.

If you can only travel in one window, March or April is the safest, and May works if you can cope with heat. If you must travel in autumn, base the trip in the north and the south and treat the central coast as a flexible stop. If you must travel in summer, shift the weight to the central coast and keep the north and south shorter.

This table is a planning aid, not a forecast. It uses the tourism board's seasonal ranges and the Foreign Office's storm and flood notes, and it gives words, not temperatures.

Read it with two filters. First, how much of your trip is outdoors: a rain day in Hanoi costs you a walk, while a rain day in Hoi An in flood season can cost you a transfer. Second, how flexible your dates are. The UK Foreign Office says the tropical cyclone season normally runs from May to November and that cyclones can happen at other times, so build a spare day into any itinerary that depends on a boat, a flight or a mountain road.

The tourism board describes September to November in Hanoi as cool with clear skies and sunshine, and April to June as warm to hot with clear skies, which makes autumn and late spring the best windows for walking the old quarter and for cruises on Ha Long Bay. In the board's description, Sapa is near-perfect in late April as flowers bloom and skies are clear, and early October is lovely when the tiered rice paddies turn golden just before harvest.

Winter, from December to March, is cool to cold in Hanoi, with mist and cloud, and the board says temperatures from late December until March can be surprisingly cold, with lows of 10 degrees. Many buildings have no heating, so pack a warm layer. Sapa and the northern mountains are colder still. Summer, June to August, is hot, humid and stormy. The Foreign Office says the rain season in the north runs from June to September, that flooding is common in and around Hanoi along the Red River, and that heat and humidity can be severe in the rainy season. If you go in summer, keep a spare day in the plan in case a bay cruise is moved or cancelled. For the mountain leg, see Hanoi to Sapa and the Sapa trekking guide.

The central coast runs on its own calendar. The tourism board describes Hoi An as warm to hot and sunny from February to August and rainy, cool and cloudy from September to January, and Hue as warm to hot and sunny from March to August and cool, rainy and cloudy from September to February. It says March is an excellent time to see Hoi An, with blossoms and greenery, that May to August can be hot enough to send you to the beach, and that from September to November Hoi An sees a lot of rain and even a few small floods. For Hue it notes occasional flooding from September to November and, in July, perfect beach weather.

The Foreign Office adds the official side: the rain season runs from October to December in central Vietnam, and seasonal flooding occurs in October and November, which can disrupt overland travel, block roads with mudslides and landslides, and damage bridges and buildings. You can still visit in those months, but build in flexibility and follow the Vietnamese National Centre for Hydro-Meteorological Forecasting, at nchmf.gov.vn, which the Foreign Office points to. For Nha Trang the board gives January to August as hot and sunny and says it has the shortest rainy season in Vietnam, and for Da Lat it gives April to October as the rainy months and November to May as cool and dry. See Hue in 2 days for planning around weather in the old capital.

The south is the simplest region. The tourism board says Ho Chi Minh City and the Mekong Delta have consistent temperatures year-round, normally around 30 degrees with sunshine, and that the city is either hot and dry or hot and rainy. From December to April it is clear and sunny, and from May to November the wet season brings a dependable afternoon downpour, usually lasting a few hours. Plan the day around that: start early and keep the afternoon flexible. The Foreign Office adds that the rain season in the south runs from June to September and that flooding is common in the Mekong Delta.

Phu Quoc follows a different rhythm. The board says its clear, hot and sunny season runs from October to June, and that from July to September storms roll through, making ferries dangerous and the beaches less than ideal. If an island week is the point of the trip, plan it for the dry months and use the Phu Quoc in 3 days guide.

Tet, the Lunar New Year, is the biggest holiday of the year. It follows the lunar calendar, so it moves each year and falls between late January and about the third week of February. Transport is under pressure in the days around it as people travel home, and many family-run shops and restaurants close for several days, though larger hotels and sights in the big cities usually keep running. Travel at Tet can work if you plan for it: book transport weeks ahead, confirm that your restaurants and tours are operating, and accept some closures.

The fixed public holidays also affect crowds. Reunification Day on 30 April and Labour Day on 1 May form a holiday stretch that fills beach resorts, and National Day on 2 September does the same. The Mid-Autumn Festival falls on the fifteenth day of the eighth lunar month, so its Gregorian date moves each year.

Avoid September to November on the central coast if your dates are fixed and you cannot absorb a flood-day detour, and avoid the Hue and Hoi An leg altogether in those months if your trip depends on a motorbike loop or an outdoor schedule. Avoid June to August in Hanoi and Ha Long Bay if a bay cruise is the headline, if you dislike heat and humidity, or if you have little room for a cancelled day. Avoid December to March in the north if you want a clear view of the limestone islands or dislike cold mist, and avoid it in Sapa unless you want winter scenery and are ready for cold.

Avoid May to November in Ho Chi Minh City only if you cannot work around afternoon rain, because the rain is predictable and the mornings are often clear. Avoid July to September on Phu Quoc if an island week is the whole point. Avoid the Tet week if you depend on public transport and open restaurants, and the weeks around 30 April, 1 May and 2 September if you want quiet beaches.

For a two- or three-week trip through the whole country, aim for March to May, avoiding Tet if you want open restaurants and easier transport. If you can only travel in summer, spend more time on the central coast and less in the north and south. If you are traveling in October or November, base yourself in the north, where the weather is at its best, and allow extra time on the central coast in case of storms.

Before you book flights, check whether you need a visa for the length of stay you want. The guide to Vietnam's e-visa and visa exemption explains the options and where to apply officially. Compare data options in the connectivity guide, check cover in the travel insurance guides, and use the transport guide to think through the long north to south legs.

Pack for more than one climate if you are covering the whole country. In winter, Hanoi and the north need a warm layer and a light rain jacket, while Ho Chi Minh City is hot enough for summer clothes. In summer, bring clothes that dry fast and a compact umbrella for the afternoon storms in the north and south.

Pagodas and temples expect covered shoulders and knees in every region. For a Ha Long Bay cruise or a Mekong boat trip, a dry bag keeps a phone and passport safe from spray and sudden showers.