Hoi An Weather in September
September is Hoi An’s peak rainy season, with substantial rainfall and high humidity, making the weather very muggy, although temperatures seem not so high. Overall, climatic conditions are far from ideal for travel. That said, the ancient town becomes exceptionally vibrant, thanks to two distinctive festivals - Vietnam National Day and Mid-Autumn Festival - held in September.
Temperature
In September, temperatures in Hoi An are no longer extreme, but the high humidity still leaves it feeling uncomfortably hot.Daily highs generally range from 31 to 34 degrees Celsius (88 - 93 degrees Fahrenheit), rarely climbing above 36℃ (97℉), and are very likely to drop below 30℃ (86℉) by late September. Yet with humidity nearing 90%, you will constantly feel as if wearing damp clothes, with moisture lingering all around. Sites such as the Chinese Assembly Hall lack air conditioning and receive little to no breeze, so walking inside feels like stepping into a steamer, heavy and stuffy.
Night lows usually hover around 26℃ (79℉), which is widely regarded as the most comfortable temperature for the human body. You can schedule light activities like wandering the ancient town in the early morning and evening, without worrying about sweating heavily. However, nighttime lows may occasionally near 30℃ (86℉), leaving you restless and struggling to sleep without air conditioning. We therefore recommend avoiding overly aged homestays and opting for accommodation equipped with air conditioning.
Old Town in the Evening
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Precipitation
Hoi An features rainy climate in September, with an average of 19 rainy days and a monthly rainfall of 297 mm. Although precipitation is quite frequent, there is no need to worry excessively. Most of the rain comes in short showers and rarely lasts for hours on end. Your itinerary will not be completely disrupted; you only need to set aside some flexible time to adjust accordingly.Yet don’t overly underestimate the rain here. It usually comes down heavily, and you’re likely to get soaked even in a raincoat. The roads also flood rapidly, making it quite dangerous to sightsee in the rain. We suggest staying at your hotel when it rains. If you don’t want to waste the time, you can browse nearby handicraft shops and enjoy the local specialties.
Typhoon
Hoi An enters its typhoon season in September. On average, the area is affected by one typhoon during this month each year. As a typhoon passes by, it usually brings two types of extreme weather: powerful, destructive winds capable of uprooting trees and tearing off roofs, and persistent torrential rain that can last continuously for one to two days, with daily rainfall accumulating up to 500 mm. Such extreme conditions can severely disrupt travel plans. For your personal safety, stay indoors and avoid going out during the typhoon until it has fully passed.Daytime / Sunshine Duration
In September, Hoi An sees sunrise at around 5:35 and sunset at around 17:49, with more than 12 hours of daylight each day. Although daylight hours are ample, frequent daily showers and midday heat greatly narrow down the golden window for outdoor activities. Thankfully, rainfall mostly occurs in the afternoon. Mornings are relatively cooler and clear, with soft, pleasant light - ideal for photographing the town’s bright yellow ancient buildings and the glistening waters of the Thu Bon River.Important note: In September, Hoi An’s UV index can peak above 11, placing it in the extreme category. While most visitors take full sun-protective measures on bright, sunny days, it’s easy to lower your guard during cloudy or rainy weather. Bear in mind that ultraviolet radiation can pass effortlessly through clouds. Even with no direct sunlight, you should keep your skin well protected to avoid painful sunburn.
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Packing List for Visiting Hoi An in September
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For the lower body: Pack some shorts, skirts, and thin pants. For footwear, prepare sneakers or hiking shoes for extensive walking, and beach shoes or flip-flops for trips to the shore. To deal with puddles left after rain, a pair of sports sandals is highly recommended - they are waterproof and stay securely on your feet.
Festivals & Events in Hoi An in September, 2026
While the climate of Hoi An in September is less than ideal, the town is full of vibrancy with two major festivals. Vietnam’s National Day is on September 2nd, and the Mid‑Autumn Festival, which falls on the 15th day of the 8th lunar month, takes place on September 16th, 2026. During these festive days, you can enjoy a host of unique experiences.
Around National Day, every alley in Hoi An’s ancient town is decorated with Vietnamese national flags, creating a vibrant and joyful festive atmosphere. Along the streets, you can sample special snacks including Vietnamese baguettes and local sweet treats, while enjoying live performances of traditional folk music and Ao Dai fashion shows.
Hoi An during the Mid-Autumn Festival is steeped in classic oriental tradition. Lively dragon and lion dances can be seen throughout the ancient town. You can join locals in the traditional rituals of moon appreciation and moon worship, and try making Vietnamese-style mooncakes yourself. When night falls, don’t miss the grand lantern ceremony along the Thu Bon River. Purchase a handcrafted lantern by the river, make a wish, and gently set it afloat on the water for an immersive taste of Hoi An’s unique Mid-Autumn romance.
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Tips
1. Please stay updated on typhoon warnings and avoid traveling during typhoon-affected days. At such times, most sites in the Hoi An will be closed, flights are very likely to be delayed or canceled, and significant safety hazards will exist.
2. In case of heavy downpours, stay away from low-lying parts of the ancient town and coastal beaches, as you may get trapped by floodwaters. When heading out after rain, be careful of wet, slippery roads to avoid accidental slips and falls.
3. During the Vietnam National Day and Mid-Autumn Festival, Hoi An sees a massive surge in visitors, with streets and alleys extremely crowded. Please be mentally prepared for this in advance. If you prefer a quieter, less crowded experience, it’s best to schedule your trip outside these periods.
