Best Time to Visit Phong Nha: Weather Month by Month
Short answer: the best time to visit Phong Nha is April to August, when it is dry, hot and the cave water is at its clearest turquoise. March and early September are good quieter months on either side. September to December is the rainy season, with October the wettest month, but it is not a closed season: our E Cave tours run every day and only stop for storms or floods. January and February are cool and grey with light drizzle rather than heavy rain. Below is the weather month by month and what it means for a cave trip.
Phong Nha weather month by month
The figures below are long-term averages for Dong Hoi, the nearest city with a weather station. Phong Nha is about 45 km inland among the mountains and can be a little cooler and wetter, but the pattern through the year is the same.
| Month | High / low | Rain (rainy days) | What it means for a cave trip |
|---|---|---|---|
| January | 22 / 17°C | 59 mm (12) | Cool and grey, drizzle more than downpours. Quiet. Swimming feels chilly |
| February | 22 / 18°C | 40 mm (11) | Similar to January. Lunar New Year (Tet) falls on 6 February in 2027, when Vietnamese families travel |
| March | 25 / 20°C | 43 mm (11) | Warming up and drying out. A good month with few people |
| April | 29 / 22°C | 61 mm (9) | Dry season starts. Children from age 5 can join our E Cave tour from now until August |
| May | 32 / 25°C | 116 mm (10) | Hot, with the odd afternoon storm. The 30 April and 1 May holiday is busy |
| June | 34 / 27°C | 79 mm (7) | Hot and dry. Vietnamese school holidays begin, so book a few days ahead |
| July | 34 / 27°C | 76 mm (7) | Hot and dry. Peak holiday month: book 3 to 5 days ahead |
| August | 33 / 26°C | 166 mm (11) | Still hot, with more showers towards the end of the month |
| September | 31 / 24°C | 473 mm (16) | Rainy season begins. Tours run. Minimum age on our E Cave tour rises to 10 |
| October | 28 / 23°C | 649 mm (19) | The wettest month and the main flood risk. Tours run unless a storm or flood makes the route unsafe |
| November | 26 / 20°C | 319 mm (17) | Rainy and cooler. Muddy trails, few visitors |
| December | 23 / 18°C | 125 mm (14) | Rain easing, cool days. Good for trekking if you do not mind a grey sky |
Source: Vietnam Institute for Building Science and Technology climate data for Dong Hoi (QCVN 02:2022/BXD). Averages hide the extremes: a single typhoon in October can bring more rain in a few days than the whole of June.
April to August: the dry season
This is the easiest time for a cave trip. Rain is light, trails are firmer, and the water at the mouth of E Cave is a clear turquoise that looks unreal in photos. It is also the season when our E Cave tour takes the youngest guests, from age 5.
The catch is heat. Days reach 33 to 34°C from May to August, and the jungle is humid. Inside the caves it is cooler, which is one reason a cave tour is a good way to spend a hot day. Start early, drink more than you think you need, and wear long, light clothes against insects. In June, July and on public holidays, book 3 to 5 days ahead.
September to December: the rainy season
Most of the year’s rain falls in these four months, and October alone averages 649 mm. Floods are most likely in October and November, and some boat trips and river caves in the area close when the water is high. Many multi-day expeditions, including Son Doong, also pause for part of this period, so check before you plan around one.
Rain on its own does not cancel our tours. E Cave and Golden Cave with E Cave run every day, and we postpone only when a storm or flood makes the route unsafe. If that happens, we message you on WhatsApp as early as we can, and you can move to another date for free or take a full refund. For most of the season the water in E Cave turns a deep jade green; after a very heavy downpour it can run brown for 3 to 5 days before it clears. Expect mud on the trail, and note that the minimum age on the E Cave tour is 10 from September to March. Our rainy season guide covers this in detail.
January to March: cool and quiet
After December the heavy rain stops, but the sky often stays grey and there is light drizzle on about one day in three. Highs are around 22°C in January and February, which is comfortable for walking but makes swimming less inviting. Trails can stay muddy into January. By March it is warmer and drier, and it is one of the quietest good months to visit. The exception is Tet, the Lunar New Year, when Vietnamese families travel and some local businesses close for a few days.
Best time to visit Phong Nha, by what you want
- Clear turquoise water and photos: April to August.
- Families with young children: April to August, when our E Cave tour takes children from age 5.
- Fewer people: March, and September outside the Vietnamese holidays.
- Trekking without the heat: December to March. Pack a light rain jacket.
- A trip you cannot move: any month works for our E Cave tours, but in October and November leave a spare day in case of a postponement.
Whenever you come, see our packing list for a cave trek and our Phong Nha itinerary for 1, 2 or 3 days.
Frequently Asked Questions
Is October a bad time to visit Phong Nha?
+
It is the wettest month, with about 19 rainy days, and floods are possible, so some boat trips and river caves may close. It is not a write-off: our E Cave tours still run every day unless a storm or flood makes the route unsafe. Leave a spare day in your plans in case we need to postpone.
Is Phong Nha too hot in summer?
+
Days reach 33 to 34°C from May to August and the jungle is humid, so the walk is the hard part. The caves themselves are cooler, and on our E Cave tour the afternoon is spent swimming and paddling at the cave entrance. Start early, drink plenty and wear light long sleeves.
When is the water in E Cave clearest?
+
In the dry months, from about April to August, it is a clear turquoise. In the rainy season it turns a deep jade green, and after a very heavy downpour it can run brown for 3 to 5 days before clearing. Paddling inside the cave works the same in every colour.
Can I visit Phong Nha in December or January?
+
Yes. The heavy rain is mostly over by December, days are around 22 to 23°C and there are few visitors. Expect grey skies, light drizzle and muddy trails, and bring a light rain jacket. Our E Cave tours run every day; the minimum age is 10 at this time of year.
Plan your trip
Whatever the month, the E Cave tour through Abandoned Valley runs daily from $68 per person, and Golden Cave and E Cave in one day from $82. If you are not sure which cave trip suits you, see our Phong Nha cave tours compared.