The northeast monsoons finally begin in Central Vietnam as the month progresses, with storms on the horizon, although the high temperatures of summer begin to dip. Although the region still enjoys some sunny days, beach-goers no longer have any guarantees of sunshine.
And hiking in Dalat and the Central Highlands is a soggy adventure, while even some caves at Phong Nha may be off-limits due to flooding. Hue, Hoi An, and northern Central Vietnam generally get more rains than Nha Trang and south Central Vietnam, which sees more dry, sunny days. And the region is prone to typhoons during fall months. Be sure to pack your raingear along with your sunscreen.
By contrast, the monsoon rains of North Vietnam begin to lessen, especially as October approaches, and temperatures drop towards the comfort zone again in Hanoi, while the mountains will be temperature to cool. By late September, trekking in the mountains of Sapa, Mau Son, and Mu Cang Chai is again a viable option, as sunny days become the norm. This is a great time to explore Hanoi and the highlands.
However, in South Vietnam the monsoon will linger through October, with frequent, heavy and often prolonged rain the norm. And temperatures remain high, averaging 81°F (27.5°C). These are usually in the afternoon, and you can still expect plenty of sunny and dry daylight hours. After really heavy and prolonged week-long rains, you'll probably experience some flooding, while the South China Sea can be rough, and transportation delays are likely (it’s wise to have a backup plan in mind in the event that “rain stops play”).
Crowds & Costs
Visitor numbers remain relatively low in September. and prices are at an all-time low. Hence, you get the best of both worlds as few (if any) tourist sites are crowded, although visitor numbers see an upturn in Northern Vietnam. Flights from the US West Coast are at their cheapest in September, although hotel prices vary little from month to month.
Where to Go
It’s all change in September as the focus shifts from the beaches and cities of Central Vietnam to the once-again sunny idylls of northern Vietnam. This is a great time to explore Hanoi as the skies clear (however, the seas can be stormy and rough in September in Halong Bay, so save that for October or beyond).
Weather is still unpredictable, so pack a light umbrella. Hanoi’s “milk flower” (Alstonia scholaris) blossoms in September, and the streets are perfumed with its unique scent. Try to time your visit for September 2 to witness the massive celebrations that mark Vietnam’s capital on National Day.
Ninh Binh—about 55 miles (95 km) south of Hanoi—resembles Ha Long Bay, but on land. It’s far less well-known, yet is a Nirvana for adventure-oriented activities. To get here, hop aboard the “Reunification Express” for the 3-hour train ride. Then, after checking off a sightseeing wish-list (including the Gothic Phat Diem Cathedral and various pagodas, including Bai Dinh, the largest pagoda in South East Asia), explore by boat through the rice paddies and cave-riddled mountains of Trang An and Tam Coc.
Although it is still rainy season in South Vietnam, this is a good month to explore the Mekong Delta, as the waterfront and water-borne life is at its most active and fascinating. Locally grown fruits, such as dragon fruit and mango, are at their prime. And this is still off-season, so you can enjoy exploring without the crowds, plus tourist prices are generally at their lowest.
What to Do
Hike the mountains of North Vietnam this month. It's a fantastic time of year for photographers, especially around the hillsides of Sapa and Mu Cang Chai, where the terraced rice fields turn golden and ready to harvest, brilliant under the glorious sunshine. The scene is made more photogenic by the many colorfully dressed Hmong ethnic minority farmers who work the fields in their traditional attire.
Take a bicycle tour of Hanoi. It’s the most authentic way to explore this charming colonial city alongside the locals themselves. Your route should include the alleys along the Red River and the temples of Thuy Khue (West Lake).
National Independence Day. Celebrated nationwide on September 2, this is one of the most significant holidays in the Vietnamese calendar and marks the day revolutionary leader Ho Chi Minh declared Vietnam's independence from France. Expect exuberant festivities and fireworks.
Tet Trung Thu (Mid-Autumn Festival). This fun end-of-September festival (held on the 15th day of the eighth month of the lunar calendar) features lion dances and fanciful red lanterns to help a legendary moon-bound figure back to Earth. It’s popular with children, who get special entertainment, toys, and treats such as moon cakes.
Traveling to Vietnam in September? Check out these great itineraries
Vietnam Nature & Culture Tour: Hanoi, Hue, Ho Chi Minh City and more – 17 days. Explore the cultural and natural highlights of Vietnam north to south, and leave few stones unturned.
Hidden Beauty of North Vietnam – 6 days. September is a great time of year to head from Hanoi up into northern Vietnam for six days of highland exploration.