Two centres, and the month that decides them
Every tour operator sells Bangkok with a beach. What none of them tells you is that Thailand's two coasts are about three months out of step, so the same fortnight is either the best trip in the country or a week of rain, depending on which beach and which month. The table below is that answer for seven combinations, computed rather than recommended.
Computed, not recommended
Which combination works when
A month is green when every place in the combination is under 150mm and has fifteen or fewer rain days. It is red when any of them is above 250mm. The current month is outlined.
| Combination | J | F | M | A | M | J | J | A | S | O | N | D | Good months |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Bangkok and Phuket | January: good | February: good | March: good | April: mixed | May: avoid | June: mixed | July: mixed | August: mixed | September: avoid | October: avoid | November: mixed | December: good | 4 |
| Bangkok and Koh Samui | January: good | February: good | March: good | April: good | May: mixed | June: mixed | July: mixed | August: mixed | September: avoid | October: avoid | November: avoid | December: mixed | 4 |
| Bangkok and Chiang Mai | January: good | February: good | March: good | April: good | May: mixed | June: mixed | July: mixed | August: avoid | September: avoid | October: mixed | November: good | December: good | 6 |
| Phuket and Krabi | January: good | February: good | March: good | April: mixed | May: avoid | June: mixed | July: mixed | August: avoid | September: avoid | October: avoid | November: avoid | December: good | 4 |
| Chiang Mai and Phuket | January: good | February: good | March: good | April: mixed | May: avoid | June: mixed | July: mixed | August: avoid | September: avoid | October: avoid | November: mixed | December: good | 4 |
| Bangkok, Chiang Mai and Phuket | January: good | February: good | March: good | April: mixed | May: avoid | June: mixed | July: mixed | August: avoid | September: avoid | October: avoid | November: mixed | December: good | 4 |
| Phuket and Koh Samui | January: good | February: good | March: good | April: mixed | May: avoid | June: mixed | July: mixed | August: mixed | September: avoid | October: avoid | November: avoid | December: mixed | 3 |
ERA5 reanalysis, 1995 to 2024, at each place's own coordinates. Journey times from the routes we have checked.
The widest window belongs to Bangkok and Chiang Mai, at 6 months of the year. The narrowest belongs to Phuket and Koh Samui, at 3. Both are on the same map and neither fact appears in a brochure.
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Bangkok and Phuket
Works in December to March
The default first trip to Thailand: a few days of city, then a beach on the Andaman. Ninety minutes of flying between them and the busiest domestic route in the country, so the connection is never the problem.
Watch for this. Phuket's window is narrow. December to March, and by late April the afternoons are wet.
- Bangkok to Phuket 1h 30m by flight
-
Bangkok and Koh Samui
Works in January to April
The same trip on the other coast, and the one to take when the Andaman is in its monsoon. Koh Samui is dry from January to September; the reason this pairing scores only four months is Bangkok, which is wet from May. For a northern summer, go to Samui and keep Bangkok to a night at each end.
Watch for this. Not in November. Koh Samui's wettest month of the year is November, at 313mm.
- Bangkok to Koh Samui 1h 5m by flight
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Bangkok and Chiang Mai
Works in November to April
City and mountains, no beach, and the widest weather window of any pairing here. The overnight sleeper between them replaces a hotel night and is a better journey than the flight.
Watch for this. The northern burning season runs February to April. The rainfall is fine and the air is not.
- Bangkok to Chiang Mai 1h by flight
-
Phuket and Krabi
Works in December to March
Two bases on the same coast, seventy kilometres apart, with completely different landscapes: Phuket's beaches and nightlife against Krabi's limestone and its car-free bays.
Watch for this. Same coast means the same season. When one is wet the other is wetter: Krabi takes more rain than Phuket in every month of the year.
- Phuket to Krabi 1h 30m by ferry
-
Chiang Mai and Phuket
Works in December to March
Mountains and the Andaman, the two ends of the country. There is no checked direct route between them, so it is a flight through Bangkok or a stop there in the middle.
Watch for this. Chiang Mai is at its best from November, Phuket from December. December to March is where the two windows overlap.
- Chiang Mai to Phuket no checked route; usually a connection through Bangkok
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Bangkok, Chiang Mai and Phuket
Works in December to March
The standard two weeks: a few days of city, a few days of mountains, a week on a beach. Three centres is the most a fortnight will take without becoming a tour of airports.
Watch for this. Three places means the narrowest window of the three, which is Phuket's. December to March.
- Bangkok to Chiang Mai 1h by flight
- Chiang Mai to Phuket no checked route; usually a connection through Bangkok
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Phuket and Koh Samui
Works in January to March
Both coasts in one trip, which sounds like the complete Thailand and is the one combination on this page with a real trap in it.
Watch for this. The two coasts are dry together in January, February and March, and in no other month. Outside those three, one of them is always in its wet season.
- Phuket to Koh Samui 55m by flight
Start from the month instead
If your dates are fixed and the destinations are not, work the other way round.
Frequently asked questions
Can I combine Phuket and Koh Samui in one trip?+
Yes, in January, February and March. Those are the only months when both are under our dry threshold at the same time, because the Andaman and the Gulf run about three months out of step. In every other month one of the two is in its wet season, and in October and November both are.
What is the best multi-centre combination for Thailand?+
It depends on the month more than on the places. Bangkok and Chiang Mai works in November to April, which is 6 months of the year; Phuket and Koh Samui works in January to March. Pick the month first and the combination second.
How many places should a two-week Thailand trip cover?+
Three is the practical limit and two is often better. Every move costs half a day at least, and on this network the moves that look shortest on a map are not always the quickest: Phuket to Koh Samui is 261km and can take ten hours by road and ferry.
Is it better to fly or go overland between centres?+
Fly for anything crossing the country. Bangkok to Phuket is ninety minutes in the air against roughly twelve hours on the road, and Phuket to Koh Samui is under an hour against six to ten. Overland is worth it on the short hops, like Phuket to Krabi, and on the Bangkok to Chiang Mai sleeper, which replaces a hotel night.