30YearWeather
Halong Bay in May
Halong Bay weather in May - Vietnam
🌧️Wet Season

Halong Bay Weather in May

Plan your May trip to Halong Bay, Vietnam. Based on 30 years of NASA data, expect temperatures of 29°C (high) to 25°C (low), with 48% rain probability and 8 hours of daily sunshine. The Coastal Waters averages 29°C in May. Pack rain gear for around 31 rainy days.

Avg High
29°C

Hottest around day 31

Avg Low
25°C

Coolest around day 1

Rainy Days
31days

48% avg rain chance

Sunshine
8hrs/day

Spring season

Sea Temperature in May

Coastal Waters(Ocean)

29°C

Monthly Average

Water Feel
🌴Tropical

Perfect for swimming and water sports

Swim Rating
Excellent for swimming

Based on average sea surface temperature

Body of Water
Coastal Waters

Ocean

Halong Bay coastline

Halong Bay May Weather Calendar

Click any day to see detailed weather information

Currency

VND

Vietnamese đồng

Language

Vietnamese

Driving

Right side

Safety

High Safety

GPI: 1.786

Travel Intelligence

Exclusive flight analytics & health data for Halong Bay

Smart Flight Estimator

Airport-to-Airport Logistics

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Flight Connectivity Analysis

Airport traffic data & seasonal patterns

Remote
10/ 100
Traffic Index

Off the beaten path

Peak Daily Arrivals

0

slots per day

Peak

Jul

Low

Dec

Monthly Traffic Distribution

20
Jan
21
Feb
18
Mar
21
Apr
20
May
19
Jun
25
Jul
23
Aug
22
Sep
20
Oct
19
Nov
17
Dec
Traffic Level
Low Season

Key Connections

Ho Chi Minh City Tan Son Nhat (SGN)
Da Nang (DAD)
Nha Trang Cam Ranh (CXR)
Seoul Incheon (ICN)
Dalat Lien Khuong (DLI)

Health & Safety Advisory

CDC travel health recommendations

10 Recommendations
COVID-19

All eligible travelers should be up to date with their COVID-19 vaccines. Please seeYour COVID-19 Vaccinationfor more information.

Chikungunya

All travelers should take steps to prevent mosquito bites. Chikungunya vaccination is generally not recommended. Travelers who wish to consider vaccination can visit “What to consider before traveling” on thechikungunya vaccinespage to learn more.

Hepatitis A

Recommended for unvaccinated travelers one year old or older going to Vietnam.Infants 6 to 11 months old should also be vaccinated against Hepatitis A. The dose does not count toward the routine 2-dose series.Travelers allergic to a vaccine component should receive a single dose of immune globulin, which provides effective protection for up to 2 months depending on dosage given.Unvaccinated travelers who are over 40 years old, are immunocompromised, or have chronic medical conditions planning to depart to a risk area in less than 2 weeks should get the initial dose of vaccine and at the same appointment receive immune globulin.

Hepatitis B

Recommended for unvaccinated travelers of all ages traveling to Vietnam.

Japanese Encephalitis

Recommended for travelers whoAre moving to an area with Japanese encephalitis to liveSpend long periods of time, such as a month or more, in areas with Japanese encephalitisFrequently travel to areas with Japanese encephalitisConsider vaccination for travelersSpending less than a month in areas with Japanese encephalitis but will be doing activities that increase risk of infection, such as visiting rural areas, hiking or camping, or staying in places without air conditioning, screens, or bed netsGoing to areas with Japanese encephalitis who are uncertain of their activities or how long they will be thereNot recommended for travelers planning short-term travel to urban areas or travel to areas with no clear Japanese encephalitis season.

Malaria

CDC recommends that travelers going to certain areas of Vietnam take prescription medicine to prevent malaria. Depending on the medicine you take, you will need to start taking this medicine multiple days before your trip, as well as during and after your trip. Talk to your doctor about which malaria medication you should take.Transmission areasRural areas only; rare cases in the Mekong and Red River DeltasNone in the cities of Da Nang, Hai Phong, Hanoi, Ho Chi Minh City (Saigon), Nha Trang, and Quy NhonDrug resistanceChloroquine and mefloquineSpeciesP. vivax(55%)P. falciparum(44%)P. knowlesi,6P. malariae, andP. ovale(rare)Recommended chemoprophylaxisProvinces of Bình Dương, Bình Phước, Đắk Lắk, Đắk Nông, Gia Lai, Khánh Hòa, Kon Tum, Lâm Đồng, Ninh Thuận, Tây Ninh: Atovaquone-proguanil, doxycycline, tafenoquine2All other areas with malaria transmission (except Mekong and Red River Deltas): Atovaquone-proguanil, doxycycline, mefloquine, tafenoquine2Mekong and Red River Deltas: No chemoprophylaxis recommended (insect bite precautions and mosquito avoidance only)4Updated April 23, 2025See footnotes

+4 more

Source: CDC Travelers' Health

View Complete Health Guide

Is May a Good Time to Visit Halong Bay?

👌Good option with minor considerations
Short Answer

May brings storm season risk to Halong Bay. While typical weather is 29°C with 48% rain, plan for potential disruptions and secure cancellation-friendly bookings.

Decision Factors

Typhoon season active

Western Pacific zone - expect potential typhoon activity

Oppressive heat and humidity

29.1°C with 85% humidity - challenging conditions

Vaccinations required

Yellow Fever

Feels significantly hotter than 29.1°C

Heat index: 36°C due to 85% humidity

Warm tropical seas

29°C sea temperature - Hot Soup

Frequent rainfall expected

48% chance of rain - pack waterproofs

Good For

  • 💼
    Business travelers

    Climate-controlled meetings unaffected by weather

Who Should Avoid

  • 👴
    Elderly travelers

    Heat index of 36°C poses health risks

  • 💼
    Business travelers

    Storm season may cause flight disruptions

  • 🌡️
    Heat-sensitive visitors

    36°C feels-like temperature creates discomfort

930 observations30-year historical data
Confidence: 99%

"According to 30YearWeather's analysis of 30 years of NASA POWER satellite data,Halong Bay in May averages 29°C with 48% precipitation probability."

📊 Source: 30YearWeather.com🛰️ Data: NASA POWER (1991-2021)View Methodology →

Frequently Asked Questions: Halong Bay in May

What are the temperatures in Halong Bay in May?

Daytime highs average 29°C, nights drop to 25°C. Temperatures remain fairly consistent.

How many rainy days in Halong Bay in May?

Expect around 31 days with measurable rainfall. An umbrella is advisable.

What to wear in Halong Bay in May?

Light, breathable fabrics. Don't forget sunglasses and a hat.

Is May peak season in Halong Bay?

This is off-peak season. Expect lower prices and fewer crowds.