The best time to visit Vietnam and Cambodia on one trip is late January to March. In February, Siem Reap averages 3.8 mm of rain, Ho Chi Minh City gets 8 mm, Da Nang is down to 22 mm from 658 mm in October and Hanoi's average high is a mild 21.3°C (70.3°F).
The two countries share a border, not a calendar. Cambodia has one dry season and one wet one; Vietnam runs three climates at once, and its central coast floods in October and November, just as Cambodia starts to dry out.
Late January to March: The Window That Works for Both
The window opens in late January because that's when Da Nang dries out. Its January normal is 83 mm of rain over 14 days, falling to 22 mm over 7 days in February, and March (36 mm) and April (50 mm) stay low.
Cambodia is ready earlier. Siem Reap averages 7.4 mm of rain in December, 4.3 mm in January and 3.8 mm in February, and Phnom Penh gets 3.3 mm in February. Down south, Ho Chi Minh City is dry from December to April.
Hanoi is the one stop where "dry" needs a footnote. Its 19 mm of February rain is spread over 12 days, and March's 55 mm over 18, counting any day with 0.1 mm or more. Expect drizzle and gray skies, not downpours, and February lows of 16.2°C (61.2°F).
The window closes in March for a different reason: heat. Siem Reap's average high is already 34.6°C (94.3°F) in March. Late January and February suit a trip built around Angkor; March suits one weighted toward Vietnam.
Three Vietnams and One Cambodia: Why the Rain Never Lines Up
Canada's travel advice for Vietnam puts the rainy season at June to September in the north and south and October to December in the center, with typhoons usually arriving between June and December. Cambodia has a single wet season, so the four regions compare like this:
- The north (Hanoi): cool and drizzly from December to March, then hot and wet, peaking at 335 mm in August.
- The center (Hue, Hoi An, Da Nang): dry through the summer, then soaked, with 394 mm in September at Da Nang.
- The south (Ho Chi Minh City and the Mekong Delta): dry from December to April, then a wet season that Vietnam's tourism authority says "brings a dependable afternoon downpour" from May to November.
- Cambodia: little rain from December to February, then Siem Reap jumps from 47.5 mm in April to 143.0 mm in May and peaks at 305.2 mm in September.
The edges are where trips go wrong. In November, Hanoi and Cambodia dry out while Da Nang has its second-wettest month; in May, it's the reverse. For Vietnam alone, see the best time to visit Vietnam, region by region.
Month by Month: Vietnam and Cambodia Weather Side by Side
Rain decides most trips, so the table gives average monthly rainfall. Vietnam's figures are 1991 to 2020 normals from the Viet Nam Meteorological and Hydrological Administration, and Cambodia's cover 1982 to 2024, from its Ministry of Water Resources and Meteorology, both published by the World Meteorological Organization.
| Month | Vietnam: Hanoi / Da Nang / HCMC | Cambodia: Phnom Penh / Siem Reap | Verdict |
|---|---|---|---|
| January | 28 / 83 / 12 mm | 20.2 / 4.3 mm | Good; Da Nang still showery |
| February | 19 / 22 / 8 mm | 3.3 / 3.8 mm | Best month for both (mind Tet) |
| March | 55 / 36 / 18 mm | 63.0 / 41.3 mm | Very good; Angkor heating up |
| April | 79 / 50 / 57 mm | 54.3 / 47.5 mm | Good for Vietnam, hot at Angkor |
| May | 188 / 71 / 202 mm | 116.6 / 143.0 mm | Rains reach the south and Cambodia |
| June | 231 / 68 / 224 mm | 138.4 / 194.9 mm | Green season; center driest |
| July | 300 / 92 / 231 mm | 148.6 / 169.9 mm | Green season; center driest |
| August | 335 / 167 / 219 mm | 153.4 / 169.7 mm | Wet north and south |
| September | 195 / 394 / 273 mm | 252.9 / 305.2 mm | Worst month for both |
| October | 126 / 658 / 240 mm | 242.1 / 227.0 mm | Skip central Vietnam |
| November | 48 / 486 / 128 mm | 93.7 / 61.8 mm | North and Cambodia improve |
| December | 24 / 272 / 41 mm | 29.2 / 7.4 mm | Good if you skip the center |
Read across a row, not down a column. By our reading of the WMO normals, February is the only month with all five cities under 25 mm, and September is the only one with all five over 190 mm.
Temperature matters at the extremes. Hanoi's average high runs from 20.0°C (68°F) in January to 33.8°C (92.8°F) in June, while Ho Chi Minh City's stays between 31.6°C (88.9°F) and 34.9°C (94.8°F) all year. Cambodia's highs run from 30.2°C (86.4°F) in Phnom Penh in December to 35.3°C (95.5°F) in Siem Reap in May.
Tet 2027: A Holiday in the Middle of the Best Window
Lunar New Year's Day falls on Saturday, February 6, 2027, and Vietnam's public-sector Tet break runs seven straight days, from Thursday, February 4 to Wednesday, February 10, under a Ministry of Home Affairs notice of October 9, 2026. If your dates touch that week, book transport and rooms early.
The bigger catch is paperwork. Vietnam's immigration law gives Immigration 3 working days to decide an eVisa once it has the complete application and the fee, and Tet wipes 5 working days off the February calendar: the 4th, 5th, 8th, 9th and 10th. Count on 3 to 5 working days in a normal week and longer around the holiday. That timeline belongs to Vietnam Immigration, not to us; we can file, chase and correct, but we can't move an approval up the line.
⚠️ If you arrive in February 2027, apply in January. We recommend applying at least 1 to 2 weeks before travel in any month, and Tet removes 5 working days from February.
Central Vietnam in October and November: The Season to Take Seriously
Da Nang averages 658 mm of rain in October and 486 mm in November, and by our math October alone beats Hanoi's July and August combined (635 mm). Canada's travel advice flags seasonal flooding in central Vietnam in October and November, and Vietnam's tourism authority says that from September to November, Hoi An "sees a lot of rain and even a few small floods."
That doesn't rule out a fall trip. It rules out building one around Hue, Hoi An and Da Nang. In November, Hanoi gets 48 mm, Siem Reap 61.8 mm and Phnom Penh 93.7 mm, so spend the Vietnam leg in the north, fly over the center and finish in Cambodia as it dries out.
⚠️ Keep central Vietnam bookings refundable in October and November. Averages can't tell you which week will flood. Watch the forecast for Hue, Hoi An and Da Nang before you go, and have a plan B that skips the coast.
Angkor From March to May: Beat the Heat at 5 a.m.
From March to May, Cambodia hits its hottest stretch: Siem Reap's average high reaches 34.8°C (94.6°F) in April and 35.3°C in May, and Phnom Penh's peaks at 34.9°C in April. Vietnam, by contrast, is at its peak: its tourism authority says "March to May offers the best weather countrywide." Khmer New Year falls in mid-April, right in that heat.
The ticket rules let you work around it. Angkor Enterprise opens the park at 5 a.m. and closes it at 6:30 p.m., and its 3-day pass can be used on any 3 days within 7, so you can see temples from sunrise to late morning, rest through the afternoon and come back another day. As listed on October 15, 2026, passes cost $37 for 1 day, $62 for 3 days and $72 for 7 days, the last usable within 30 days.
The Green Season: When the Tonle Sap Runs Backward
Cambodia's wet months, May to October by the normals, fill its great lake. According to the Mekong River Commission, high Mekong flows force the Tonle Sap River to reverse and flood the Great Lake, which grows six-fold at the flood peak, from around 2,500 square kilometers to around 15,000. At the end of the wet season, the river turns back downstream, and Cambodia celebrates with the Water Festival (Bon Om Touk), next held November 23 to 25, 2026, with boat races.
In Vietnam, June and July make the central coast the dry one, with 68 mm and 92 mm at Da Nang against 231 mm and 300 mm in Hanoi. At a June average high of 34.9°C (94.8°F) in Da Nang, it's beach weather, and typhoons usually arrive between June and December, so keep plans flexible.
Route Order: Let the Season Pick the First Country
The order you travel in can buy better weather at both ends. Four patterns work, and our Vietnam itinerary ideas fill in the Vietnam leg:
- Late January to March: Cambodia first while it's driest, then Vietnam from south to north, reaching Hanoi in March as its average high climbs to 23.5°C (74.3°F).
- November to mid-January: Hanoi first while the north is dry, a flight over the wet center, then the south and Cambodia, where Siem Reap is down to 7.4 mm by December.
- March to May: Cambodia first, in March, before the heat peaks, then Vietnam at its best.
- June and July: Vietnam's central coast, which stays under 100 mm a month, and Cambodia in its green season.
Visas for Two Countries: Single or Multiple Entry
Cambodia's visa is a separate application to Cambodia. US, UK, Australian, Canadian and EU ordinary passports aren't on its visa-exemption list, and its tourist visa is single entry, gives 30 days from the date of entry and takes 3 working days to process.
For Vietnam, first check whether you need a visa. If you do, the eVisa is valid for up to 90 days, single or multiple entry, and your route decides which. Cambodia first or last means one entry into Vietnam, so single entry is enough. A loop out to Cambodia and back needs multiple entry, which costs $30 more on a one-month eVisa ($84 against $54) and $10 more on a three-month one ($104 against $94), stamp fee included; see our multiple-entry eVisa prices.
⚠️ A single-entry eVisa doesn't cover a side trip to Cambodia. It's good for one entry, and its end date doesn't move while you're away, so days in Cambodia still count. A five-week loop of Hanoi, Siem Reap and Ho Chi Minh City outlasts the 30 days of a one-month eVisa and needs the three-month multiple-entry version.
Vietnam Visa by BDA is a private company. We're not affiliated with the Vietnamese government, and you can apply yourself at evisa.gov.vn for only the $25 single or $50 multiple stamp fee. Either way, an eVisa only works at border gates on the government's list, which includes Moc Bai on the Phnom Penh road. Name the gate you'll actually use.
Getting Between Them: Fly, or Take the Bus Through Moc Bai
Fly into Phnom Penh and you'll land at Techo International (KTI), which replaced the old PNH airport on September 9, 2025. Cambodia asks you to select KTI, not PNH, on visa applications.
By road, Giant Ibis runs a sleeper bus from Siem Reap to Ho Chi Minh City: 550 km (342 miles) in a scheduled 12 hours. From Phnom Penh, the trip is 240 km (149 miles) and 6 hours via the Bavet and Moc Bai crossing, and the company won't board you without a printed Vietnam eVisa, though it prints them free at its offices. That's the operator's rule, not Vietnam's.
⚠️ If Bangkok is in the plan, fly. UK travel advice updated October 12, 2026 says land crossings between Thailand and Cambodia remain suspended, so as of mid-October 2026 the old overland route from Bangkok through Cambodia to Ho Chi Minh City is out.
A Few Parting Notes
Every figure on this page is a long-term average; once your dates are close, trust the forecast. For health paperwork, Cambodia asks for a yellow fever certificate only if you're arriving from a listed transmission-risk country; for routine vaccinations, ask a travel health clinic.
Your eVisa arrives as a PDF you download from Vietnam Immigration's eVisa site. Vietnam's immigration law describes printing it, and the bus from Cambodia insists on paper, so carry a printed copy and keep one on your phone.