Vietnam Climate in General
Vietnam spans several climatic zones, resulting in substantial weather condition variations between the north and the south. Average temperatures year round range from 20 to 35 degrees Celsius so there is no particularly good or bad time to visit Vietnam. When it comes to weather, it’s a tough call, as Vietnam’s climate is so diverse. Think frosts and occasional snow in the mountains of the north, and temperatures soaring to 40°C in the south during the dry season. Vietnam’s weather is dictated by two monsoons. The winter monsoon comes from the northeast between October and March, bringing damp and chilly winters to all areas north of Nha Trang, and dry and warm temperatures to the south. From April or May to October, the summer monsoon brings hot, humid weather to the whole country except for those areas sheltered by mountains. For the best balance, try the months of April, May or October. For those sticking to the south, November to February is dry and a touch cooler. From July to November, violent and unpredictable typhoons hit centrel and northern Vietnam, which can dampen the spirits of even the most enthusiastic traveler. It gets pretty crowded from November to March and in July and August
Ho Chi Minh City (Saigon) and the South is hot year-round and there are two seasons. The wet season lasts from May to November and the Dry season from December to April. The wet is characterised by high humidity levels and a refreshing afternoon downpour. Humidity in the south during the months of June and July ranges between 75% and 85%. The hottest period is March to May when average daytime temperatures can reach 35 degrees Celsius (95 degrees Fahrenheit). Typically this involves an afternoon downpour that rarely interferes with travel arrangements
Central Vietnam is usually dry from May to October and wet from December to February. October and November may experience unstable weather conditions and flooding
Hanoi and the north experience Four seasons.
Summer (May to October), is hot and wet with regular downpours and occasional typhoons. July and August are the hottest months with maximum temperatures exceeding 33 degrees Celsius (91 degrees Fahrenheit). Winter (November to April) is usually cold and humid. The winter months from November to April are usually cold and humid. The months of December and January can be particularly cool with temperatures as low as 8 degrees Celsius (46 degrees Fahrenheit) Cloudy skies and misty conditions usually prevail.. Temperatures can drop to 0 degrees Celsius in Sapa (in the highlands near the Chinese border) in winter.
When to go and where to ride
Hanoi and its southeast provinces
All year around will be fine, but remember bring sunglasses and Sunscream during Summer
The best time to visit Hanoi is around September to November or from March to April for their milder temperatures and pleasant weather.
Hanoi experiences the typical climate of northern Vietnam, where summers are hot and humid (temperatures can climb up to a maximum of 35°C), and winters are, by national standards, relatively cool and dry, with a warm humid subtropical climate (when temperatures can drop to as low as 6°C – 7°C). Summers, lasting from May to September, are hot and humid, receiving the majority of the annual 1,680 millimetres (66.1 in) of rainfall. The winters are short, relatively dry, and mild , while spring can bring light rains
The Tet holiday (Lunar New Year’s Eve) is in the Spring. Flowers are the most beautiful during this time of the year. The weather starts to warm up with light rain here and there during the week. Hanoians believe that these light rains bring prosperity and luck for the New Year.
The Summer, on the other hand, is quite intolerable. The heat alone would be alright but there is the humidity which would start to manifest in the air since Spring. Visitors also have to be very careful with mosquitoes because there are a lot in Hanoi due to the level of moisture in the air and the temperature. Hanoi has a good climate for many insects to proliferate, not just mosquitoes.
There is something unique about Hanoi’s Autumn. The weather is perfect with less humidity in the air. The temperature would drop by now, offering people a chance to take out their fleece and jackets. Moreover, there is this type of tree – “cay hoa sua” which only has flowers in Autumn. The flower has a very distinct smell. If you have the chance to visit Hanoi during Autumn, make sure you ask the local people about this type of trees and where you can experience their distinct aroma.
Winter can be quite brutal because it is not only cold but also very humid. What makes it feel like the winter in Hanoi is colder than elsewhere is the fact that Vietnamese houses don’t have a central heating system. Many houses don’t have any types of heating at all.
► Mountain Bike Tours: from September to January, but but remember bring more warm clothes during Winter
► Non-Cycling Tours: Best time is from April to September, warm clothes are need to be brough with you.
The climate of Hoang Lien Nature Reserve is unique to Vietnam. It is highly seasonal, with a subtropical climate in the summer and a temperate climate during the winter. Mean annual temperature for Sa Pa town is 15.4°C, with a maximum of 29.4°C and a minimum of – 5°C. The warmest months are July and August, and the coldest months are December and January. Snow falls in some years on the highest peaks.
In common with the rest of northern Vietnam, Hoang Lien Nature Reserve experiences a marked wet season from May to September, with the heaviest rainfall occurring in July and August. Humidity ranges from 75 to 91 percent with a yearly mean of 86 percent.
Climate varies considerably within the nature reserve. The prevalent wind direction for most of the year is west to east, leading to cloud formation on the upper slopes of the Fansipan massif. These high-altitude areas are covered by cloud most days of the year and have very high humidity. Cloud also penetrates into the valleys but these areas are usually less humid than the mountain slopes. In the extreme east of the nature reserve, around Ban Ho village, mean temperatures are considerably higher due to the lower altitude of these areas.
All year around will be fine for cycling tours and non-cycling tours
The best time to visit Mekong Delta would probably be September to March
Raining in Mekong Delta usually rains only lasts for maximum an hour then it will back to normal as sunshine. The Mekong Delta, as a region, lies immediately to the west of Ho Chi Minh City, roughly forming a triangle stretching from MY Tho in the east to Chau Doc and Ha Tien in the northwest, down to Ca Mau and the South China Sea at the southernmost tip of Vietnam, and including the island of Phu Quoc.
The Mekong Delta region of Vietnam displays a variety of physical landscapes, ranging from mountains and highlands to the north and west to broad, flat flood plains in the south. This diversity of terrain was largely the product of tectonic uplift and folding brought about by the collision of the Indian and Eurasian tectonic plates about 50 million years ago. The soil of the lower Delta consists mainly of sediment from the Mekong and its tributaries, deposited over millions of years as the river changed its course due to the flatness of the low-lying terrain
Climate change concerns
Being a low-lying coastal region, the Mekong Delta is particularly susceptible to floods resulting from rises in sea level due to climate change. The Climate Change Research Institute at Can Tho University, in studying the possible consequences of climate change, has predicted that, besides suffering from drought brought on by seasonal decrease in rainfall, many provinces in the Mekong Delta will be flooded by the year 2030. The most serious cases are predicted to be the provinces of Ben Tre and Long An, of which 51% and 49%, respectively, are expected to be flooded if sea levels rise by 1 meter
Same with Ho Chi Minh City, Mekong Delta Region has a tropical climate. The average humidity level is 68%, average temperature is 26 ~ 28 °C. The city is generally warm, and has a rainy season from May to November and a dry season from December to April.
On the bright side, Vietnam climates vary so much, you can usually find sunshine, any time of year. Vietnam is an all year round holiday destination. Many prefer the cooler weather from Sept – April.
The tropic of Cancer lies 23.5° north of the equator. Vietnam is 9° – 23° north, equal to 1650 km from north to south. The northernmost point of Vietnam is ½º inside the Tropic of Cancer! One would think all Vietnam is therefore tropical, but, the weather in Vietnam isn’t quite that simple.
Vietnam weather is best described as: complicated or diverse. Although Vietnam is in the tropics, it is also attached to Asia. This allows: temperate continental weather, to extend below The Tropic of Cancer into North Vietnam. North of Hue there are four seasons: spring, summer, autumn & winter.
The Hai Van mountains range, south of Hue, forms a barrier against the cold northerly winds which blow into Northern Vietnam from China. There’s a distinct difference in climate, north & south of Hue, this is where: North Vietnam’s temperate climate, meets the tropical climate of South Vietnam. Hue gets some of the wettest weather in Vietnam & floods regularly.
From Da Nang – Phan Thiet: the climate is essentially tropical. Transitions between wet & dry season feel a bit like spring & autumn, but: they are not as distinct as in North Vietnam & winter is milder. The major factor affecting Central Vietnam weather is the tropical monsoon. Central Vietnam coastal towns flood after several days rain over the central highlands of Vietnam.
South of Phan Thiet, the climate is entirely tropical. There are two seasons: wet & dry season, with a month transition between seasons, typically bringing heavy afternoon downpours. Rain is heavier in the south than in Central Vietnam: after more than 2 hrs rain, storm drains block causing flooding. Monsoon is the only factor determining the climate of South Vietnam. Dry season is hot & humid.
Throw into the pot: the monsoon migrates north over the year, random typhoons from Sept – Dec, & year on year variation when the monsoon arrives. It all gets rather complicated.