Cat Ba island weather
Current conditions
Averages and extremes
Yesterday's Data
Overview of Cat Ba island weather
Similar to its neighboring Halong Bay area, Cat Ba Island features a tropical monsoon climate, which is characteristic of northern Vietnam. Throughout the year, there are four distinct seasons: spring, summer, autumn, and winter. The two most dominant weather patterns are the hot, humid season and the dry, cool season.
The average temperatures on Cat Ba Island range between 25°C and 29°C. The humidity level remains relatively high at about 80%, aligning with annual precipitation that averages between 1700 and 1800 mm.
Below is a detailed guide about the weather on Cat Ba Island, featuring essential information to help you plan a seamless vacation to this beautiful destination.
Weather by Seasons
Spring (Late February-April)
Weather: Spring on Cat Ba Island is characterized by comfortable, mild temperatures ranging from 18°C to 26°C. The weather is typically cloudy and humid, with frequent drizzles. The sea temperature becomes warm, making it ideal for various water activities.
Things to do: Engage in kayaking, swimming, mountain climbing, cruising, and cycling.
Summer (May-August)
Weather: Summer sees a rapid rise in temperatures, which can reach up to 35°C. The weather is often stifling hot, and high humidity combined with frequent rainfall can create a sweltering environment, although you may benefit from around 8 hours of sunlight daily. Nights are generally cooler.
Storms and typhoons are more prevalent in July and August, which can disrupt outdoor activities.
Things to do: Enjoy swimming, snorkeling or scuba diving, kayaking, cruising, or opt for indoor activities like visiting museums and pagodas.
Autumn (September-November)
Weather: Autumn is one of the most favorable seasons on Cat Ba Island, offering mild weather with temperatures ranging from 20°C to 30°C. The likelihood of heavy rains and storms significantly decreases, allowing for enjoyable outdoor activities.
Things to do: Participate in kayaking, mountain climbing, snorkeling or scuba diving, cruising, trekking, and cycling.
Winter (December-January)
Weather: Winter is noted as the coldest and driest season. Daytime temperatures hover between 13°C and 22°C, with cooler nights. Average humidity drops to about 70%, and sunny days decrease to around 6 hours, resulting in foggy mornings.
Things to do: Activities include cruising, trekking, mountain climbing, cycling, visiting pagodas, and enjoying the local amusement park.
Monthly Climate
January
January marks the beginning of the year and is significantly influenced by winter weather, with temperatures ranging from 13°C to 19°C. The humidity is lower, and rainfall is minimal at approximately 20 mm, creating dry conditions.
February
February is a transitional month as Cat Ba Island moves into spring, with temperatures warming slightly to between 15°C and 20°C. Drizzle and light rains are common, but outdoor activities remain viable.
March
March ushers in warmer weather, with temperatures hitting around 22°C. However, this month experiences more rainy days, with total rainfall reaching about 40 mm over 15 wet days. These conditions are excellent for swimming, kayaking, and cruising in warm sea waters.
April
As spring nears its conclusion, average temperatures can rise to a high of 26°C. Occasional rain can increase monthly precipitation to about 80 mm. The higher number of sunshine hours contributes to clear conditions ideal for outdoor activities.
May
May signals the arrival of summer and is considered one of the best times to visit Cat Ba Island. The weather is marked by more sunny and warm days, with temperatures ranging from 26°C to 35°C. Although it can be hot and humid, it remains perfect for water activities and outdoor excursions.
June
June is typically hot, with temperatures reaching up to 36°C, yet conditions remain bearable. Rainfall increases to about 235 mm, with occasional storms. The hot, humid weather makes swimming, kayaking, and snorkeling attractive options for tourists.
July
July, alongside June, is one of the hottest and wettest months. Average temperatures are around 37°C. With more frequent rain leading to total rainfall of approximately 250 mm and daily sunshine hours at the peak of 8 hours, the risk of storms and typhoons can affect planned cruises, suggesting a shift to indoor activities.
August
Rainfall can reach a high of 280 mm in August, and the weather remains scorching during the day. Overnight cruises may not be advisable, so visitors should consider cycling, trekking, or other indoor pursuits during their stay.
September
Temperatures start to cool in September, varying from 24°C to 30°C, and rain occurrences diminish, allowing for enjoyable activities such as swimming, cruising, canoeing, and kayaking.
October
October welcomes autumn with cooler temperatures averaging around 28°C, and sometimes falling to 21°C. Expect more dry and sunny days, perfect for outdoor adventures.
November
November is typically the peak tourist season for visitors to Halong Bay, attributed to its pleasant weather conditions. Average temperatures range from 20°C to 25°C, and humidity levels are relatively low, although evenings may require a sweater or light jacket. Rain becomes less frequent, with only occasional drizzles.
December
As winter sets in on Cat Ba Island, the weather turns colder with moderate rainfall. Temperatures range from 13°C to 20°C, presenting an excellent opportunity for activities like cruising, kayaking, trekking, and mountain climbing.
Best Time to Visit
The most favorable time for international travelers to visit Cat Ba Island is from November to March. During this period, visitors can enjoy stunning landscapes under clear skies while engaging in outdoor activities without the worry of sudden downpours or large crowds. Additionally, the seawater remains warm enough in spring to facilitate kayaking, swimming, and snorkeling experiences.
Local Tips
- The weather on Cat Ba Island is predictable most of the time, but it's wise to check the weather forecast carefully before your trip.
- If you plan to travel during the peak tourist season from November to March, consider booking services well in advance to avoid price increases and ensure availability.
- Spring or autumn is ideal for visiting Cat Ba, allowing you to enjoy comfortable weather, explore the national park, and indulge in delightful outdoor activities.
- While summer on Cat Ba Island is suited for beach vacations and cruise trips, be cautious of potential storms.
Weather averages by month
| Month | High / Low (°C) | Rain |
|---|---|---|
| January | 20°C / 12°C | 4 days |
| February | 20°C / 14°C | 6 days |
| March | 22°C / 16°C | 6 days |
| April | 27°C / 20°C | 7 days |
| May | 29°C / 22°C | 8 days |
| June | 32°C / 24°C | 12 days |
| July | 31°C / 25°C | 12 days |
| August | 31°C / 25°C | 13 days |
| September | 31°C / 24°C | 12 days |
| October | 27°C / 21°C | 8 days |
| November | 26°C / 18°C | 6 days |
| December | 21°C / 14°C | 2 days |
Frequently asked questions
1. What are the rainiest months in Cat Ba island?
In 2025, July and August continue to be characterized by significant rainfall and tumultuous seas. The average precipitation during these months can reach up to 140mm, reflecting ongoing climate changes. This shift emphasizes the need for preparedness among residents and visitors alike.
2. What is the hottest month in Cat Ba island?
June remains Cat Ba Island's warmest month, boasting average highs of 33°C (about 91.4°F) and lows around 26°C (about 78.8°F) in 2025. Visitors can expect pleasant beach weather, ideal for outdoor activities and exploration.
3. What is the coldest month in Cat Ba island?
From December to early January 2026, Cat Ba Island experiences its coldest temperatures and a significant increase in fog. During this period, temperatures can drop below 10°C (50°F). Travelers should prepare for chilly conditions and reduced visibility when planning their visits.
