#1Hot
Ho Chi Minh City
- Day
- 30.4°C
- Sea
- -
- Sun
- 1.5h
- Rain days
- 29
Your September weather guide
Weather in Vietnam in September
September is a reasonable month for Vietnam if warmth matters more than dry weather, but it is not a strong choice for a sunshine-led holiday. Average daytime temperatures reach 30°C, nights stay around 25°C, and rain occurs on 25 days. That means light clothing and flexible plans rather than a packed outdoor schedule. Hanoi is the better choice for fewer rainy days, while Ho Chi Minh City and Phu Quoc suit travellers more willing to work around wet weather.
Long-term climate averages, not a forecast · 1991-2020
- Average daytime high
- 29.5°Cacross 3 destinations
- Average night-time low
- 24.6°Cafter dark
- Sea temperature
- 28.7°Cwarm enough to swim
- Rainy days
- 25days1 mm or more
Vietnam, month by month
Turn up the warmth
Warmest places in Vietnam in September
Ranked by average daytime high. The full comparison is in the table below.
Vietnam destinations ranked for September
All 3 places we track in Vietnam, ordered by daytime high.
Scroll sideways for more weather, down for more places. Click a heading to sort.
| # | Destination | ||||||
|---|---|---|---|---|---|---|---|
| 1 | Ho Chi Minh City | 30.4°C | 24.1°C | - | 1.5 h | 29 | 13 h 30 min |
| 2 | Hanoi | 30.3°C | 24.1°C | - | 3.5 h | 19 | 12 h 18 min |
| 3 | Phu Quoc | 27.8°C | 25.6°C | 28.7°C | 1.3 h | 27 | 13 h 24 min |
3 destinations shownClimate averages, not a forecast.
September climate overview
Daytime highs across Vietnam in September run from 27.8°C (Phu Quoc) to 30.4°C (Ho Chi Minh City). In Ho Chi Minh City about 100% of September days reach 25°C. Nights average 24.6°C; the coldest 10% of nights in Phu Quoc fall to 24°C or below.
Rainfall in September
Expect around 25 rainy days (1 mm or more) in September, with Hanoi the driest (19 days) and Ho Chi Minh City the wettest (29 days). The wettest September at Ho Chi Minh City between 1991 and 2020 was 1995 with 407 mm; the driest was 1999 with 186 mm.
Sea temperature
The sea averages 28.7°C around Vietnam in September. That is comfortable for swimming.
Sunshine and daylight
Around 2.1 hours of sunshine a day on average, out of 12.1 hours of daylight (sunshine estimated from cloud cover).
September against the rest of the year in Vietnam
September is the 6th warmest month of the twelve in Vietnam. It is 0.5°C cooler than August and 0.7°C cooler in October. The hottest month here is May (31°C) and the coolest January (26°C).
Which part of Vietnam in September?
- Most sunshine: Hanoi, 3.5 h a day.
- Driest: Hanoi, about 19 rainy days.
- Warmest sea: Phu Quoc, 29°C.
- Hottest: Ho Chi Minh City, 30°C by day.
- Coolest (better for walking and cities): Phu Quoc, 28°C.
What to pack for Vietnam in September
Based on the averages: summer clothes for the day; a rain jacket - roughly 25 wet days; swimwear - the sea is 29°C.
Similar weather elsewhere in September
Within 1.5°C of Vietnam's September daytime average: Montego Bay (31°C, sea 30°C), Bangkok (31°C, sea 29°C), Sousse (31°C, sea 26°C), Seville (30°C), Limassol (30°C, sea 27°C). See the full ranking for September.
Where to go: Hanoi has the clearest advantage
Hanoi is the better choice if fewer rainy days matter most: it has 19, compared with 29 in Ho Chi Minh City and 27 in Phu Quoc. That is a meaningful difference for a trip built around spending time outside, although Hanoi is still far from a reliably dry option. Hanoi and Ho Chi Minh City both reach 30°C by day, so choosing Hanoi does not mean giving up warmth. Phu Quoc is cooler at 28°C, but its frequent rain makes it a weaker choice for travellers expecting dependable beach weather. Choose between them on your tolerance for rain, rather than expecting a major difference in daytime heat.
Expect warm water, limited sunshine and little evening cooling
The sea around Phu Quoc averages 29°C, so water temperature is not the drawback for a beach stay; frequent rain is. Warm water alone does not guarantee suitable swimming conditions, so judge those locally rather than from the temperature. Across Vietnam, average sunshine is just 2.1 hours, making September a poor fit if long sunny spells are your priority. Pack light, breathable clothes, a compact umbrella and waterproof protection for anything you need to keep dry. Keep outdoor plans movable rather than assuming rain will fall at a convenient time. With average nights at 25°C, do not expect evenings to offer much relief from the warmth.
A little more detail
Vietnam in September FAQs
Plain answers, grounded in the averages.
Where is the hottest place in Vietnam in September?
Ho Chi Minh City is the warmest of the 3 places we track in Vietnam in September with an average high of 30.4°C; Phu Quoc is the coolest at 27.8°C.
Is the sea warm in Vietnam in September?
The sea averages 22°C or more at Phu Quoc (29°C) in September.
How much warmer is Vietnam than London in September?
Vietnam averages 30°C by day, compared with London's 19°C. Pack for substantially warmer conditions, but not necessarily sunnier ones: frequent rain and limited sunshine mean warm-weather clothing should be paired with practical rain protection.
Which destination has the coolest nights?
Hanoi and Ho Chi Minh City both average 24°C at night, compared with 26°C in Phu Quoc. None offers particularly cool evenings. If warm nights make sleeping difficult, prioritise accommodation with effective cooling rather than relying on the temperature dropping after dark.
About these averages
ERA5-Land climate reanalysis via Open-Meteo (11 km grid), 1991-2020
Averages computed from daily values at 3 destination points.Records are the highest and lowest daily values in that 30-year period, not all-time records. These are climate averages, not a forecast for your trip. How we measure holiday weather
- Hot · 25°C+
- Warm · 20°C to below 25°C
- Mild · 15°C to below 20°C
- Cool · below 15°C