Getting around Bangkok in the rainy season: what still runs when it floods

Most rainy-season advice for Bangkok tells you to pack an umbrella. The more useful thing to know is which parts of the city’s transport network actually stop. The answer is not the one your instincts give you: the boat, which never touches a road, pauses first — and the underground metro, which sounds doomed, keeps running.

The season, in plain terms

Bangkok’s rainy season runs roughly from the middle of May into October, driven by the southwest monsoon, and September and October are the wettest months of the year by a wide margin. What that does not convey is the shape of the rain. This is not a British drizzle that greys out a whole day. It is a hard, loud, often spectacular thunderstorm that arrives in the afternoon or early evening, empties itself, and leaves the street steaming. Between storms the sun comes back.

That shape matters more than the rainfall total, because it changes the right decision. If the rain were constant you would have to travel through it. Since it usually is not, the single most effective rainy-season tactic in Bangkok is to be somewhere with a roof and a coffee for forty minutes, and let the drainage catch up. Bangkok sits on a flat river delta barely above sea level, so the problem is almost never the falling water. It is what an hour of it does to a road.

Elevated rail: the boring, correct answer

When the street below has turned into a canal, the BTS Skytrain is still gliding over it on a concrete viaduct, and so is the Airport Rail Link out to Suvarnabhumi. That is the whole argument, and it is a strong one. We looked for reporting of Bangkok’s elevated lines being suspended by rain and did not find any; the suspensions on record were caused by an earthquake and by political protests, not weather.

We would not turn that into a promise. Any railway can stop for lightning, wind, a power fault or something with nothing to do with water, so if a storm is genuinely violent it costs nothing to check the operator’s status channel before you leave. But if you are choosing a route in the rainy season and you have an elevated-rail option, take it. The rest of this page is about what to do when you do not.

The MRT is resilient, and that is a different thing from immune

An underground metro in a delta city sounds like an obvious weak point, and it is the mode people ask about most. Bangkok’s MRT was built with the objection in mind. Station entrances sit about a metre above street level rather than flush with the pavement, they are fitted with flood gates, and the network was designed against a hundred-year flood.

It is not a sealed vault. On the evening of 5 September 2025, heavy rain combined with nearby construction work sent water into the concourse at Thailand Cultural Centre station. Two of the four entrances were closed. The other two stayed open, and trains ran through the station normally while it was cleaned up. That single incident is, we think, the most honest way to hold the MRT in your head: the system keeps moving, but a specific entrance can shut with no notice, so know where the other ones are.

Boats are the first to pause

The Khlong Saen Saep canal boat is one of the great shortcuts in Bangkok, a fast cheap line straight through traffic that road users can only envy. In the rainy season it is also the least reliable thing in this guide. When heavy rain raises the canal, the low bridges over it stop being passable, and the boats simply cannot get under them. On one occasion service was suspended from six in the morning until noon, with the operator warning it would extend the halt if the water stayed high. There is no published water-level rule you can look up and plan around; it is a pattern, not a policy, which is precisely what makes it awkward. If the canal boat is load-bearing in your commute, keep a rail alternative in mind from June onwards.

The Chao Phraya river boats hold up better, but not perfectly. When the river runs high the operator coordinates with the Royal Irrigation Department, drops boat speed, and can suspend calls at individual piers — so the service may be running while the specific pier you wanted is closed. Check before you build a day around it.

Roads and buses: where the rain actually reaches you

Everything above the road keeps working. Everything on it does not. Bangkok’s drainage has improved a great deal since the 2011 flood — the city says it has raised drainage capacity from 60 to 80 millimetres an hour, has four giant drainage tunnels running with a fifth in testing, and has built flood barriers higher than the 2011 peak — and yet a single bad downpour in November 2025 still flooded 57 locations across the city at once.

Some corridors turn up in the flood reports again and again: Ratchadaphisek around Chatuchak, where water has been reported between 15 and 50 centimetres deep; Phahonyothin near Kasetsart University; and stretches of Sukhumvit and Srinakarin. A BMTA city bus has no way around any of it. It is in the same water as the cars, on a fixed route, and it is the one mode where a storm can turn a predictable trip into an open-ended one.

Grab, taxis and the price of wanting a car in the rain

A car door-to-door is the instinctive answer to rain, and it is the one the whole city has at the same moment. Rain is a known surge trigger for Grab, and drivers become scarce exactly as demand spikes. We are being careful here on purpose: this is reported consistently by users and matches how surge pricing works everywhere, but neither Grab nor its rivals publish figures, so we will not print a multiplier and neither should anyone else. Expect it to cost more than usual and to take longer to match, and treat any specific number you read as a guess.

A street-hailed metered taxi is not surge-priced, but it is subject to the same flooded road and to the meter’s three-baht-a-minute charge while it sits in it — see our comparison of Grab and metered taxis for how that arithmetic works. Motorcycle taxis, the usual last-mile fix, become a less appealing proposition in heavy rain for reasons that need no elaboration.

What to actually check before you leave

Bangkok publishes better real-time flood information than most cities, and almost no visitor knows it exists. The Bangkok Metropolitan Administration’s Department of Drainage and Sewerage runs a public monitoring page, and the city’s rain radar — hosted by the Thai Meteorological Department, with a Nong Chok and a Nong Khaem station — shows you the storm cell approaching. The city says it monitors more than 300 automated locations and forecasts rain up to three hours ahead.

Three hours ahead is the number that should change your behaviour. It is enough to decide whether to leave now, or to sit down for a while and let a storm pass over you. In our judgment that decision — go now, or wait forty minutes — is worth more than any route choice on this page.

Quick answers

Does the BTS stop running when Bangkok floods?

Not for the flood itself — it is elevated, above the water — and we found no record of a rain-caused suspension. Storms can bring lightning and wind, so check the operator’s status channel if one is severe.

Can the underground MRT flood?

Entrances sit about a metre above the street and have flood gates, and the system was designed to a hundred-year flood standard. In September 2025 heavy rain and adjacent construction did push water into one station’s concourse and two entrances closed, but trains kept running.

Do the canal boats run in the rain?

Often not. When rain raises the Khlong Saen Saep canal, boats cannot clear the low bridges and the service is halted — once for a whole morning. River boats are steadier, but slow down and can skip individual piers in high water.

When is the rainy season and how bad is it?

Roughly mid-May to October, with September and October the wettest. It arrives as short violent afternoon storms rather than all-day rain, which is why waiting one out is usually the right call.