☀️ Weather + Seasons
👍 When to go there
🔎 Weather in Months
❓ Questions + Answers
🎫 Excursion + Tickets
🎫 Book Tickets Online
Quick answer: Cát Bà Island offers two distinct seasons: the cooler, drier months and the warm, humid rainy season. The best time to visit is spring (March–May) or autumn (September–November) when the weather is more pleasant and outdoor activities shine. Pack for variable conditions and expect fewer crowds outside of peak summer.
At a glance:
- 📍 Region: Cát Bà Island, near the southern edge of Hạ Long Bay archipelago, northern Vietnam.
- 🌡️ Temperature: Spring & autumn ~20-30 °C; summer may exceed 30 °C; winter 15-22 °C and cooler under chill wind.
- 💧 Rain & seasons: Dry season from November–March with lower rainfall; rainy/typhoon-susceptible season from May–October, peaking July–August.
- 🎯 Best time to visit: Mid-April to early June or October to November—good weather, calmer seas, and fewer crowds.
Last updated in November 2025
What is the weather in Cat Ba Island in Vietnam?
Cat Ba Island in northern Vietnam has a tropical climate with warm summers and mild winters. The island enjoys pleasant weather for most of the year, making it one of the most popular destinations near Halong Bay.
The best weather is usually from October to April, when temperatures are lower, humidity decreases and outdoor activities are more enjoyable. From Cat Ba Island you can also travel by bus and ferry to Hanoi.
☀️ Dry Season
The dry season lasts from October to April and offers the most comfortable weather for visitors.
- Temperatures around 16-28°C
- Lower humidity and less rain
- Ideal for hiking and boat trips
- Best season for sightseeing
⛈️ Rainy Season
The rainy season runs from May to September, bringing warmer temperatures and occasional storms.
- Temperatures around 28-35°C
- High humidity levels
- Frequent rain showers
- Lush green landscapes
What is the best time to visit Cat Ba Island?
🎯 Best Time to Visit
The best time to visit Cat Ba Island is from October to April, when the weather is cooler, drier and ideal for outdoor activities.
- October-November: pleasant weather and fewer crowds
- December-February: coolest months of the year
- March-April: warm temperatures and clear skies
- Book transport and accommodation in advance during holidays
Weather in Cat Ba Island throughout the year:
| Month | Weather in Cat Ba Island |
|---|---|
| January | Cool and mostly dry. Temperatures 15-20°C. Good for sightseeing and hiking, but sea activities may be limited. |
| February | Mild weather with temperatures around 16-21°C. Occasional drizzle and fog, fewer tourists. |
| March | Pleasant spring weather, 21-23°C. Comfortable for hiking, boat trips and exploring the island. |
| April | One of the best months to visit. Warm temperatures of 25-28°C and relatively low rainfall. |
| May | Start of summer. Temperatures reach 30°C, ideal for beaches, kayaking and swimming. |
| June | Hot and humid with occasional rain showers. Temperatures around 26-31°C. |
| July | Hottest and wettest month. High humidity, tropical showers and possible storms. |
| August | Similar to July. Warm sea temperatures but frequent rain and occasional typhoons. |
| September | Rainfall gradually decreases. Warm weather around 27°C with greener landscapes. |
| October | Excellent travel month. Temperatures 23-28°C, lower humidity and pleasant conditions. |
| November | Dry and comfortable weather. Great for hiking, kayaking and outdoor activities. |
| December | Cool and dry with temperatures around 18-22°C. Good for sightseeing and nature trips. |
Max, Min and Average Temperature in Cat Ba Island:
The island has a warm and humid climate with temperatures ranging from a minimum of around 15°C (59°F) in the winter months to a maximum of around 35°C (95°F) in the summer months. The average temperature in Cat Ba Island is around 25°C (77°F), which makes it a pleasant place to visit all year round, with the best time to visit from October to April when the weather is cooler and drier.
| Month | Max Temp (°C) | Min Temp (°C) | Avg Temp (°C) |
|---|---|---|---|
| January | 20 | 15 | 17.5 |
| February | 22 | 16 | 19 |
| March | 25 | 18 | 21.5 |
| April | 28 | 21 | 24.5 |
| May | 31 | 24 | 27.5 |
| June | 33 | 26 | 29.5 |
| July | 34 | 26 | 30 |
| August | 33 | 26 | 29.5 |
| Sep | 31 | 24 | 27.5 |
| October | 29 | 22 | 25.5 |
| Nov | 26 | 19 | 22.5 |
| Dec | 22 | 16 | 19 |
Rainfall and Rainy Days in Cat Ba Island:
Cat Ba Island has a humid subtropical climate with frequent rainfall throughout the year. The rainy season is from May to October, with July and August being the months with the highest rainfall levels. Visitors should expect rain during their stay, so it is recommended to bring appropriate clothing and gear. Despite the rainfall, Cat Ba Island is a popular tourist destination year-round, with visitors enjoying a range of activities and attractions.
| Month | Average Monthly Rainfall (mm) | Number of Rainy Days |
|---|---|---|
| January | 50 | 11 |
| February | 30 | 8 |
| March | 40 | 10 |
| April | 70 | 13 |
| May | 210 | 19 |
| June | 330 | 22 |
| July | 390 | 24 |
| August | 350 | 24 |
| September | 260 | 20 |
| October | 130 | 15 |
| November | 80 | 12 |
| December | 60 | 10 |
Max and Average Wind Speed and Wind Gust in Cat Ba Island:
Cat Ba Island experiences relatively strong winds throughout the year, with the highest wind speeds occurring from November to April. The average wind speeds range from 10 to 15 km/h, and visitors should be aware of the weather conditions before planning outdoor activities. It is recommended to bring appropriate clothing and gear to stay comfortable in windy conditions.
| Month | Average Wind Speed (km/h) | Maximum Wind Speed (km/h) |
|---|---|---|
| January | 12 | 30 |
| February | 12 | 30 |
| March | 13 | 35 |
| April | 15 | 40 |
| May | 13 | 30 |
| June | 12 | 25 |
| July | 11 | 25 |
| August | 11 | 25 |
| September | 12 | 30 |
| October | 14 | 35 |
| November | 15 | 40 |
| December | 14 | 35 |
Cloud and Humidity in Cat Ba Island:
Cat Ba Island has a humid subtropical climate with high levels of humidity throughout the year. The island also has frequent cloud cover due to its coastal location and nearby mountains. Visitors should expect high humidity levels and frequent cloud cover, particularly during the summer months, from May to September. It is recommended to bring appropriate clothing and gear to stay comfortable in these conditions.
| Month | Aver. Cloud Cover (%) | Aver. Humidity (%) |
|---|---|---|
| January | 40 | 82 |
| February | 35 | 81 |
| March | 30 | 80 |
| April | 25 | 79 |
| May | 20 | 78 |
| June | 20 | 78 |
| July | 20 | 80 |
| August | 25 | 81 |
| September | 30 | 82 |
| October | 35 | 83 |
| November | 40 | 83 |
| December | 40 | 82 |
Sun Hours and Sun Days in Cat Ba Island:
Cat Ba Island experiences a tropical monsoon climate and has warm temperatures throughout the year, with an average high of around 30°C in the summer and an average low of around 15°C in the winter. During the summer months, the island sees an average of 7-8 hours of sunshine per day, with occasional rain showers and thunderstorms. In contrast, the winter months are much cloudier and rainier, with only 2-3 hours of sunshine per day on average. Visitors should plan accordingly to make the most of the island’s natural beauty and attractions.
| Month | Sun Hours per Day | Sunny Days per Month |
|---|---|---|
| January | 3 | 10 |
| February | 3 | 10 |
| March | 4 | 12 |
| April | 5 | 15 |
| May | 6 | 19 |
| June | 7 | 23 |
| July | 8 | 26 |
| August | 8 | 26 |
| September | 6 | 18 |
| October | 5 | 15 |
| November | 4 | 12 |
| December | 3 | 10 |
Visibility in Cat Ba Island:
Cat Ba Island has generally good visibility throughout the year, particularly during the dry season from November to March. During this period, visitors can expect clear blue skies and bright sunshine, with visibility extending to several kilometers. However, during the wet season from April to October, visibility can be more limited due to increased humidity, cloud cover, and occasional rain showers. Fog and mist can also occur, particularly in the early morning hours.
| Month | Visibility (km) |
|---|---|
| January | 6-10 |
| February | 6-10 |
| March | 6-10 |
| April | 4-6 |
| May | 4-6 |
| June | 4-6 |
| July | 4-6 |
| August | 4-6 |
| September | 4-6 |
| October | 4-6 |
| November | 6-10 |
| December | 6-10 |
What is the sea temperature in Cat Ba Island:
The sea temperature in Cat Ba Island ranges from 23°C to 30°C throughout the year, with the warmest temperatures usually occurring from June to September. During the cooler months of December to March, sea temperatures can dip to 23-24°C, while temperatures can reach up to 30°C or higher in the warmer months. The sea temperature is generally comfortable for swimming year-round, although temperatures can vary depending on location and other factors. Visitors should check local sea conditions before swimming or participating in water activities.
| Month | Sea Temperature (°C) |
|---|---|
| January | 23-24 |
| February | 23-24 |
| March | 23-24 |
| April | 25-27 |
| May | 27-29 |
| June | 29-31 |
| July | 29-31 |
| August | 29-31 |
| September | 28-30 |
| October | 27-29 |
| November | 25-27 |
| December | 23-24 |
❓ Frequently Asked Questions – Weather in Cat Ba Island
What is the weather like in Cat Ba Island?
Cat Ba Island has a tropical climate with warm summers, mild winters and temperatures ranging from 15°C to 35°C throughout the year.
When is the best time to visit Cat Ba Island?
The best time to visit is from October to April, when the weather is cooler, drier and ideal for outdoor activities.
When is the rainy season in Cat Ba?
The rainy season usually lasts from May to September, with the highest rainfall in July and August.
Can Cat Ba Island be affected by typhoons?
Yes, typhoons occasionally affect Cat Ba between July and September. Always check local weather forecasts before traveling.
What should I pack for Cat Ba Island?
Pack light clothing, comfortable shoes, sunscreen and rain gear. Read also: What to Pack for Vietnam.
Can you swim in Cat Ba Island?
Yes, swimming is possible for most of the year, especially from April to October when sea temperatures are warmer.
Is sunscreen necessary in Cat Ba?
Yes, UV levels can be high, especially in summer. Sunscreen, sunglasses and a hat are recommended.
Are mosquitoes common in Cat Ba?
Yes, mosquitoes are common, especially during the rainy season. Insect repellent is recommended.
What is the average temperature in Cat Ba Island?
Average temperatures range from 20°C in winter to 30-35°C during the hottest summer months.
Can I go hiking in Cat Ba National Park?
Yes, Cat Ba National Park offers several hiking trails and viewpoints. Comfortable shoes and water are recommended.
Where can you travel from Cat Ba Island?
You can travel by ferry and bus to Ninh Binh, to Hanoi or via Hanoi to Sapa.
What are the most popular islands in Vietnam?
Popular islands include Phu Quoc, Cat Ba and Con Dao. See also Best Islands in Vietnam.
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