What September feels like in Hanoi
September falls in Hanoi's wet season — the rainfall numbers rise clearly above the dry months. Afternoons are hot, so sightseeing works best in the morning or evening. There is little difference between day and night: nights stay warm, and evenings feel much like the afternoon. The air is muggy, so it feels hotter than the thermometer suggests.
Rain in Hanoi in September
Rain is part of normal life this month, falling on most days. Rainy days are intense, averaging about 14.8 mm (0.6 in) — downpours rather than drizzle. That is heavier than Hanoi's usual 11.6 mm per rainy day across the year. It is among the three wettest months of the year.
Daylight and sunshine in September
Mid-month, Hanoi gets 12 h 17 min of daylight, from sunrise near 5:43 am to sunset near 6:01 pm. Days are getting shorter: 35 min less daylight than in mid-August. Measured sunshine covers about 65% of the daylight — there are plenty of bright spells.
How September compares to the rest of the year
Ranked by average high, September comes out as the 5th warmest month in Hanoi. Afternoons run 1.1°C (2°F) cooler than in August, with 53 mm less rain. October is cooler again. The next month's average high: 28.4°C (83.1°F).
Who September suits
- Sightseeing: less ideal — rain falls on more than half the days.
- Parks & outdoor: less ideal — afternoons are too warm to linger outside.
- Museums & indoor: a good choice — with rain on most days, galleries and museums make easy plans.
Tips for visiting Hanoi in September
Rain Protection
A compact umbrella and a light waterproof jacket.
Sun Protection
Sunscreen, a hat and sunglasses; light breathable clothes.
Quick questions
How warm is Hanoi in September?
Expect around 30.5°C (86.9°F) in the afternoon and 24.5°C (76.1°F) at night, which most visitors would call hot.
Does it rain a lot in Hanoi in September?
It does: about 20 rainy days bring roughly 297 mm, so plan some indoor options.
What should I wear in Hanoi in September?
Based on the averages: rain protection and sun protection. There is little need to change for the evening.
Is September or October better for visiting Hanoi?
On our 12-month climate ranking, October comes out ahead (#7 of 12 vs #9). October is cooler and has fewer rainy days.