Vietnam has an incredibly diverse climate influenced by both tropical monsoons and the range of altitudes and latitudes with temperatures ranging from 4°C (39°F) in the mountains in winter to sweltering and humid 36°C (97°F) days in Saigon in the middle of the dry season. In general, the weather is marked by two distinct seasons: the northeast monsoon from October to early April, and the south-west monsoon from April to September.
Weather in Saigon
Saigon is consistently warm and humid, averaging around 28°C (82°F) during the day and barely drops in temperature overnight. From April to November, the south-west monsoon causes heavy tropical downpours in the afternoon and often predictable, hour-long bursts of torrential rain. Travel in Vietnam is seldom influenced by the rain and the monsoon is often the best time for photography as dramatic thunderheads float across the Mekong delta and rice fields are a vibrant emerald-green.
Weather in Hanoi
The weather in Hanoi is most influenced by the northeast monsoon, which causes a cool winter from November to March with low average temperatures of 15°C (66°F) and highs of 23°C (73°F). The temperature in Hanoi in winter can drop as low as 10°C (50°F). Summer begins from the middle of April with high temperatures averaging 32°C (90°F) in July. The wettest months in Hanoi are July-August.
Weather in Sapa
Sapa, in Vietnam’s north, has some of the most varied climate in the country with a subtropical summer and temperate winter. Temperatures reach 29°C (84°F) in June-July and occasionally snows in late December when temperatures drop to 4°C (39°F). The wet season from June to October is the best time of year to see the terraced rice fields, with harvest occurring from September to October. From November through February, we recommended that you pack a warm jacket, gloves and beanie.
Weather in Halong Bay
Halong Bay is often shrouded in mist and like Hanoi, most influenced by the northeast monsoon which brings hotter days and rain from May to September. June is the warmest month in Ha Long Bay with an average temperature of 29°C (84°F) and the coldest is January with an average temperature of 17°C (63°F). Weather in Halong Bay can change quickly, so we recommend you include a warm jacket/fleece and rain jacket.
Weather in Dalat
At 1,500 m (4,900 ft) above sea level, the hill station of Dalat in Central Vietnam was established because of the weather; a French colonial escape from steamy Saigon. The temperature ranges from minimum temperatures around 14°C (57°F) and maximums around 24°C (75°F).