Quick Summary: Ha Long Bay weather is best from October to November, with 22.3–25.0°C and 9–11 rain days a month. Summer is hot with frequent rain and storm risk, while winter is cool with misty mornings.
Ha Long Bay is a sea of limestone islands, so the weather decides what you can actually do on the water. Calm autumn days give crisp views, while summer squalls and winter mist can cover the karsts in minutes.
Ha Long Bay Weather at a Glance
- Best months: October and November (22.3–25.0°C, 9–11 rain days a month). April is also good (24.0°C, 12 rain days).
- Average temperature: from 17.0°C in January to 28.9°C in June.
- Wet and storm season: June to September, with 22–26 rain days a month. August peaks at 26 rain days.
- Cool season: December to February, 17.0–18.1°C, with only 5–8 rain days a month.
Best Time to Visit Ha Long Bay
October and November give the best Ha Long Bay weather for a cruise. Temperatures are 22.3–25.0°C, rain days fall to 9–11 a month, and the water is usually calmer. April is a good spring option with 12 rain days.
December has the fewest rain days of the year (5), but it is cool at 18.1°C. February and March often bring mist and drizzle, which looks moody but can limit views. Summer is the risky season: rain days climb to 22–26 a month, and storms can suspend cruises.
Ha Long Bay Weather by Season
- Winter (December–February): 17.0–18.1°C, 5–8 rain days a month. Cool and dry, with fog on some mornings.
- Spring (March–April): 20.9–24.0°C, 11–12 rain days a month. Mild days, with mist and drizzle in March.
- Summer (May–September): 27.0–28.9°C, 19–26 rain days a month. Hot, humid, with sudden storms.
- Autumn (October–November): 22.3–25.0°C, 9–11 rain days a month. Clear skies and the most comfortable cruising weather.
For monthly climate averages measured over 1991–2020, see Climate-Zone.com’s Hạ Long climate normals.
Daily Weather & Humidity Insights
- Humidity: it is high most of the year, so summer days feel sticky and clothes dry slowly.
- Wind on the water: nights and mornings on deck feel much colder than the winter daily average of 17.0–18.1°C suggests.
- Sea conditions: the water is cool in winter, so most visitors skip swimming and choose kayaking or cave visits instead.
- Sudden storms: summer thunderstorms and strong wind can build quickly. Local authorities may suspend boat trips during storms.
What to Wear and Pack
- Windbreaker and sweater: useful on the deck even on summer evenings.
- Sun protection: sunscreen, sunglasses and a hat for open decks.
- Footwear: flat, non-slip shoes for wet decks and cave steps.
- Rain and motion: a light rain jacket, and seasickness tablets if you are sensitive to choppy water.
Essential Local Tips
- Go out early: kayaking, cave visits and viewpoints are best in the morning, when it is cooler and quieter.
- Prepare for typhoon season: storms are most likely from June to October. Choose a flexible or refundable cruise, check the forecast 48 hours before, and follow crew and authority instructions.
- Pick your mood: October–November gives clear views, while February–March gives misty, moody photos. Just accept that mist means shorter views.
Ready to plan the rest of your trip? See more things to do in our full Ha Long Bay travel guide.
