Hanoi Weather in September

In September, Hanoi enjoys relatively pleasant weather. The city bids farewell to sweltering heat and the year’s rainiest period, yet typhoons become more likely. With itinerary being well planned, it remains a good off-peak travel option.

Temperature

As September arrives, the temperature in Hanoi begins to drop gradually.

In the first half of the month, the high temperature ranges between 32 and 35 degrees Celsius (90 -95 degrees Fahrenheit). While there’s still lingering summer heat, the conditions are perfectly bearable. Bringing a small portable fan can effectively ease the stuffiness. The low temperature hovers at 25 to 27℃ (77 - 81℉), so you won’t break into a profuse sweat when heading out in the early morning or evening.

The weather becomes considerably cooler in the second half of the month. The high temperature mostly ranges from 30 to 33℃ (86 - 91℉), occasionally dropping to around 28℃ (82℉). As you take a leisurely stroll through the old quarter, light sweat will be quickly dried by the gentle breeze. The low temperature can fall to roughly 24℃ (75℉), so you won’t need to rely heavily on air conditioning while sleeping at night.

Precipitation

Hanoi sees frequent, heavy rainfall in September, though precipitation gradually declines. The city records an average monthly rainfall of around 265 mm, with rain falling on 14 days throughout the month. Short, intense downpours are the norm. These showers arrive fiercely, blurring visibility and shrouding streets in thick rain curtains, while water accumulates rapidly into small streams on the ground. Thankfully, such showers pass quickly, usually ending within one to two hours. The sky often clears up while you finish dining at a roadside shop.

Typhoons

Unfortunately, September marks Hanoi’s peak typhoon season, with up to two typhoons striking the city averagely. For example, between September 25th and 30th, 2025, Hanoi was hit by two typhoons, Ragasa and Bualoi, in just five days. They bring extremely powerful winds that can tear down signs from roadside shops and even uproot trees. They also trigger torrential, continuous rainfall, which can flood the streets severely, with water levels rising to thigh-deep.

Daytime and Sunshine Duration

Hanoi enjoys 12 to 12.5 hours of daylight in September. The sun rises at 5:39 - 5:46, and sets at 17:47 - 18:14. Such ample daylight allows you to freely arrange a variety of outdoor activities. The average daily effective sunshine duration is around 6 hours. However, mornings bring far more pleasant weather: heavy clouds and rainfall are rare, and the clear skies result in stunning photographs. In contrast, afternoons are relatively overcast.

In addition, UV radiation eases slightly this month. Though less intense than in peak summer, it still reaches Level 11. Without adequate sun protection, even mild exposure can lead to tanning or sunburn; severe exposure can inflict significant damage to your skin and eyesight.

Is September a Good Time to Visit Hanoi?

Judging by weather conditions alone, September is not the ideal time to visit Hanoi. However, when taking all factors into account, it is by no means the worst option.

To begin with, the sweltering summer heat has passed, making the temperature far more pleasant. Additionally, it is not the rainiest period of the year; although typhoons may strike, their impact usually lasts only a short time. What’s more, September features Vietnam National Day and the Mid-Autumn Festival, allowing you to immerse yourself in a lively festive atmosphere. Lastly, as the number of visitors remains relatively low, September is the shoulder season, with more affordable travel costs.

Packing List for Visiting Hanoi in September

Opt for summer clothing made from cotton, linen or quick-drying fabrics, including short-sleeved T-shirts, lightweight shirts, shorts and dresses. Temperatures dip slightly in the early morning and evening, and air conditioning in indoor venues tends to be powerful. Therefore, keep a thin long-sleeved cardigan on hand. Additionally, make sure to pack a lightweight waterproof jacket or disposable raincoat, and pair them with anti-slip flat casual shoes or sandals.

Note: If you plan to visit local temples, palaces and other religious sites, it is advisable to bring a pair of light and thin pants or a knee-length dress to meet the dress code requirements of the scenic spots.

Vietnam September Festivals

1. Vietnam National Day

September 2nd marks Vietnam National Day. During the festival, Vietnamese national flags are hung across every street and alley. Many locals dress in clothing printed with the national flag pattern and go out to celebrate. Some scenic spots also host festive song and dance performances. Even roadside dessert shops launch special cakes adorned with the national flag pattern, filling the entire city with an exceptionally strong festive atmosphere.

2. Mid-Autumn Festival

Vietnam’s Mid-Autumn Festival falls on the 15th day of the 8th lunar month, which corresponds to September 25, 2026. The city is steeped in a rich traditional festive atmosphere during this period. For instance, in the old quarter, nearly every shop displays colorful lanterns shaped like rabbits and the moon. You can stroll along the streets to admire the glorious lanterns, or even purchase some as souvenirs. Besides, you can easily find and taste traditional mooncakes from roadside stalls and shops.

Tips

1. It is suggested that you plan your itinerary flexibly: if it rains, you can temporarily switch to street shops or indoor attractions for sightseeing; once the weather clears up, you can continue your outdoor tours. Try not to arrange your itinerary too tightly; sudden weather changes could disrupt your plans and prevent you from completing your intended activities.

2. After the rain, try to avoid going to low-lying areas with accumulated water. Pay special attention to hidden pits under the water and loose manhole covers to prevent tripping and getting injured.

3. During the two festivals, there will be a large flow of visitors, making it extremely difficult to hail a taxi at major scenic spots and commercial districts. You can book a vehicle in advance, or walk to nearby public transport stops and travel by bus or subway.