September · Vietnam
Best time to visit Ha Long Bay in September Weather, crowds & prices
Weather in Ha Long Bay in September
Average temperature 28°C, 459 mm of rain, about 15 days with 6+ hours of sunshine and 85% humidity — based on the five most recent complete years of ERA5 data (2021–2025).
September score
3.0/10
Ranked #12 of 12 months
- Avg temp
- 28°C
- Rainfall
- 459 mm
- Humidity
- 85%
- Days with 6h+ sun
- 15
- Crowd Density
- Quiet / Uncrowded
- Average Expenses
- $ · Budget Friendly ($)
September in Ha Long Bay scores 3.0/10 for nature and wildlife travel - ranked #12 of 12. Expect around 28°C, 459 mm of rain, and roughly 15 days with 6+ hours of sunshine this month.
Ha Long Bay's limestone towers rise from green water, with overnight junks, cave visits, and kayaking among the islands.
September in Ha Long Bay: expect compromises
Days in September average 28°C (82°F) and humidity near 85% — front-load outdoor plans before the heat builds and treat the middle of the day as indoor time.
Expect monsoon-level rainfall at 459 mm: only about 15 days with 6+ hours of sunshine across the month, and stretches of heavy rain are normal.
That is 3/10 on the same scale — 12th of 12 months, versus 8/10 for the best month here.
Pack the lightest breathable clothing you own, a hat, and more water than feels necessary, a proper rain shell rather than an umbrella, footwear you can get muddy.
Expect low-season pricing, and crowds are light for this destination.
If your dates are flexible, November is materially better in Ha Long Bay — 5 points higher on the same scale.
Frequently asked
- What is the weather like in Ha Long Bay in September?
- In September, Ha Long Bay averages 28°C, 459 mm of rain, and about 15 days with 6+ hours of sunshine. Its climate-comfort score is 3.0/10.
- Is September a good time to visit Ha Long Bay?
- September earns a 3.0/10 climate-comfort score. Use the year-round chart to weigh the weather against your budget and crowd preferences.
- How much does it rain in Ha Long Bay in September?
- Expect about 459 mm of rain in September. Average humidity is 85% and there are about 15 days with 6+ hours of sunshine.
Curated in Ha Long Bay
Tickets & experiences
Things to do in Ha Long Bay
Ha Long Bay, Vietnam. Live activities and tours from GetYourGuide, matched to this destination.