Vietnam Hanoi Weather in September — Climate Guide
September in Hanoi is high
September is high for Hanoi.
September is the monsoon tapering month — rainfall drops from 320mm in August to 250mm, rainy days from 17 to 14. The Halong Bay cancellation rate falls to 15-25% (better but still risky). The Vietnamese National Day (September 2) brings a 3-day public holiday + atmospheric military parades at Ba Dinh Square.
The Mid-Autumn Festival (Tết Trung Thu, varies mid-September to early October) is the photogenic highlight — Old Quarter's Hang Ma Street transforms into the most-magical lantern market in Vietnam. Silk dragons, paper stars, fish-shaped lanterns hung in dense displays. Mooncakes everywhere. Children's processions with paper lanterns. The most magical 2-week window for Old Quarter photography.
Travel score
Monsoon tapering + Mid-Autumn Festival lantern peak
September Weather at a Glance
September averages 88°F / 31°C highs and 75°F / 24°C lows with 14 rainy days and 250mm rainfall — monsoon tapering. Humidity 84%. UV 9. Sunshine 6 hours. Conditions transitioning toward autumn by month-end.
September Travel Advice
Mid-Autumn Festival (Tết Trung Thu, varies mid-Sept to early-Oct) most-magical Old Quarter window. Hang Ma Street lantern photography peak. Halong Bay cruises 75-85% reliability (better than summer). Vietnamese National Day (Sept 2) brief crowds. Last month before October autumn pricing surge.
Flying In from Overseas
Tourist arrivals climb late month as autumn approaches. Korean autumn break (varies, Chuseok mid-September) brings brief Korean spike. European autumn shoulder begins. Direct flights from Seoul $350-550, Tokyo $350-550, Singapore $200-400, Bangkok $80-150.
September Pricing Trends
Late-monsoon shoulder pricing: Old Quarter 3-star $45-90/night, Sofitel Metropole $380-580, Capella $380-580. Halong Bay overnight cruise $140-280. Flights from Seoul $350-550. Mid-Autumn Festival weekend +20-30%.
Hanoi September Weather Stats
Avg High
31°C
Avg Low
24°C
Rainy Days
14
250mm total
Sunshine
6h
Daily avg
Humidity
84%
high
UV Index
9
Very high
Wind
10 km/h
Gusts 25
Sea Temp
0°C
no swimming
Crowds
Moderate
At attractions
September Sunrise & Sunset
Air Quality
PM2.5
38 μg/m³
PM10
58 μg/m³
Status
moderate
Feels-Like Temperature & Wind
Feels like
Daytime
34°C
Nighttime
25°C
Humidity and wind affect how the actual temperature feels.
Wind
10 km/h
Max gust 25 km/h
Activities Recommended for September
September Travel Pros & Cons
Pros
- Monsoon tapering (better than Aug)
- Mid-Autumn Festival lantern atmosphere peak
- Hang Ma Street most-magical 2 weeks
- Vietnamese National Day atmospheric
Cons
- Still rainy (14 days)
- Mid-shoulder pricing
- Mid-Autumn surge during festival weekend
September Events & Festivals
- Vietnamese National Day (September 2)
- Mid-Autumn Festival (varies, mid-September to early October — lantern peak)
- Monsoon tapering
Hanoi in September — Full Picture
September is the monsoon tapering month — rainfall drops from 320mm in August to 250mm, rainy days from 17 to 14. The Halong Bay cancellation rate falls to 15-25% (better but still risky). The Vietnamese National Day (September 2) brings a 3-day public holiday + atmospheric military parades at Ba Dinh Square.
The Mid-Autumn Festival (Tết Trung Thu, varies mid-September to early October) is the photogenic highlight — Old Quarter's Hang Ma Street transforms into the most-magical lantern market in Vietnam. Silk dragons, paper stars, fish-shaped lanterns hung in dense displays. Mooncakes everywhere. Children's processions with paper lanterns. The most magical 2-week window for Old Quarter photography.
Hotel pricing remains at August levels (mid-shoulder) but flights drop as European school year starts. Korean autumn break travelers arrive late month. September is the LAST month before October's autumn perfection.
What to Wear & What to Pack
Warm + humid + monsoon tapering — light clothes + rain jacket + sweater for evening. Insect repellent essential.
Packing Checklist
Seasonal Weather Overview
Spring (Mar·Apr·May)
27.7°C
21°C
13/mo
Summer (Jun·Jul·Aug)
32.7°C
26°C
15.7/mo
Autumn (Sep·Oct·Nov)
Current28.3°C
21.7°C
9.7/mo
Winter (Dec·Jan·Feb)
20°C
14.7°C
7.3/mo
Hanoi Monthly Weather Comparison
| Month | High | Low | Rain | Sun | Humid | UV | Crowd | Price |
|---|---|---|---|---|---|---|---|---|
| 19° | 14° | 7d·25mm | 3h | 80% | 4 | Moderate | Shoulder | |
| 20° | 15° | 9d·30mm | 2h | 82% | 4 | Moderate | Peak | |
| 23° | 18° | 13d·45mm | 2h | 85% | 5 | Moderate | Shoulder | |
| 28° | 21° | 11d·90mm | 4h | 84% | 7 | Busy | Shoulder | |
| 32° | 24° | 15d·190mm | 6h | 84% | 10 | Moderate | Shoulder | |
| 33° | 26° | 14d·240mm | 6h | 83% | 10 | Moderate | Low season | |
| 33° | 26° | 16d·270mm | 6h | 84% | 10 | Busy | Shoulder | |
| 32° | 26° | 17d·320mm | 6h | 85% | 9 | Busy | Shoulder | |
| 31° | 24° | 14d·250mm | 6h | 84% | 9 | Moderate | Shoulder | |
| October (Best) | 29° | 22° | 9d·100mm | 5h | 80% | 7 | Very busy | Peak |
| November (Best) | 25° | 19° | 6d·50mm | 5h | 75% | 6 | Very busy | Peak |
| December (Best) | 21° | 15° | 6d·25mm | 4h | 75% | 5 | Very busy | Peak |
View Other Months
Hanoi September Hotel Picks
Frequently Asked Questions
Is September a good time to visit Hanoi?
Hanoi in September is high. Tourist crowds are moderate and flight/hotel prices are shoulder.
What's the average temperature in Hanoi in September?
Hanoi September averages a high of 31°C and a low of 24°C.
Does it rain much in Hanoi in September?
Hanoi September averages 250mm of rainfall over about 14 rainy days.
What should I wear in Hanoi in September?
Warm + humid + monsoon tapering — light clothes + rain jacket + sweater for evening. Insect repellent essential.
What time are sunrise and sunset in Hanoi in September?
Hanoi September sunrise is 05:50 and sunset is 18:05, with 12h 15min of daylight.
What's the air quality like in Hanoi in September?
Hanoi September air quality (AQI) averages 85, rated Moderate. PM2.5 averages 38μg/m³.
What activities are recommended in Hanoi in September?
In September, Hanoi is great for Mid-Autumn lantern photography, Old Quarter Hang Ma Street, Halong Bay overnight cruise (improving).
Is September peak season in Hanoi?
Hanoi September crowds are moderate and prices are shoulder. You can travel relatively comfortably without long queues.
Best Months to Visit Hanoi
View Other Months
Why you can trust weather guide
Based in Chiang Mai for 8+ years, with 30+ countries visited across Southeast Asia, Japan, and Europe. Every detail in this guide is primary-source verified as of April 2026, with prices auto-refreshed via live exchange rate APIs. This isn't AI-generated boilerplate — it's written from the perspective of someone who has actually been there.