Where it floods in Chiang Mai

Most of the year the Ping is the nicest thing about living in Chiang Mai. It's slow and brown and pretty at sunset. But a few times a decade it comes over its banks, and in late September and early October 2024 it did that twice in ten days, reaching the highest level ever measured in the city. People lost homes, shops and stock, and some lost far more than that. I've written this so that if you're moving here, renting, or just visiting in the rainy season, you know where the water tends to go and how to keep an eye on it.

Everything below comes from official river data and news reports from the time, all listed at the bottom. The map is my own approximate placement of the areas those reports name. It isn't an official hazard map, and a street outside a circle can still flood.

The short version

Where

Low ground next to the Ping: the Night Bazaar side, Chang Khlan, Charoen Prathet and Warorot on the west bank, Wat Ket on the east bank, and south and downstream through Pa Daet, Nong Hoi and Saraphi. The hills get a different problem: fast flash floods in Mae Rim, Mae Taeng and the Doi Suthep foothills.

When

Late in the rainy season. The river's yearly high point has landed between August and October in 34 of the last 37 years, and every big flood since 1989 peaked in August, September or early October.

How often

Low-lying areas start to flood when the gauge at Nawarat Bridge reaches 3.70 m. It reached that in 12 of the 37 years from 1989 to 2025, and went past 4.5 m four times: 2005, 2011, 2022 and 2024.

What stayed dry

In October 2024, the Old City, Nimman and the airport weren't hit by the river flood.

Flood map

Terracotta circles are areas that news reports and official warnings named in river floods. Yellow dashed circles are flash-flood areas in the hills. Green dashed circles are areas reported as dry in October 2024. Type an address or place into the box, or tap anywhere on the map, and you'll see whether that spot falls inside or near one of the circles, what happened there and the source. Use the buttons to switch between the city centre and the wider valley.

This map and the checker are a rough guide built from past flood reports, not an official hazard map or risk rating. The circles are my approximate placement of the areas those reports name, not exact flood outlines, so a street just outside one can still flood and one inside might have stayed dry. Depth varies street by street. Before you sign a lease or buy, check the official sources further down and ask the neighbours, the landlord or the shop next door what happened in 2024.

How high the Ping has risen

Everyone in Chiang Mai talks about the river in one number: the level at gauge P.1, which sits by Nawarat Bridge in the middle of town. The Royal Irrigation Department publishes the highest reading for every year since 1989. Two lines matter. At 3.70 m the river starts to spill into low-lying areas. At 4.20 m it's officially critical, because that's the top of the city's flood barriers along the bank.

The big years stand out. In 2005 the river came over its banks more than once, reaching 4.90 m on 14 August and 4.93 m on 30 September, and researchers later put those floods at around a 100-year event. Then came 4.94 m on 29 September 2011 and 4.65 m on 3 October 2022. In 2024 it went past all of them twice: 4.93 m on 26 September, then a record 5.30 m on 5 October, 1.60 m above the flood level. In 2025 the high point was a much calmer 3.91 m.

One small note if you follow the numbers closely. The Irrigation Department has said the gauge can read slightly high in a big flood, because it sits between two bridges and very high water starts to back up against them. Chiang Mai still had a genuinely huge flood in 2024, it's just worth knowing when people compare years to the centimetre.

Area by area

The Night Bazaar side of the river. Chang Khlan Road, Charoen Prathet Road, the Night Bazaar and the Warorot and Ton Lamyai markets are the classic Chiang Mai flood. They went under in 2005, 2022 and both times in 2024, and in October 2024 the water there was more than a metre deep. Tha Phae Road flooded near the bridge too. If you're looking around Tha Phae and the Night Bazaar or Wualai and Chang Khlan, the closer you are to the river, the more this matters.

The east bank. Across the river, the water in October 2024 reached as far as the Children's Court and Arcade bus terminal junction, and the Chiang Mai-Lamphun road flooded. The railway station area flooded in 2022 and 2024, and in 2024 trains started from Lampang for a while instead. Wat Ket was on the official warning list. See Riverside and Wat Ket.

South of town. Pa Daet, Pa Phrao Nok and Nong Hoi sit on low ground beside the river. Pa Daet was the worst-hit part of the municipality in 2022, both areas were inundated again in September 2024, and parts of Mahidol Road flooded in October. See Nong Hoi South and Airport and Nong Hoi.

Downstream: Saraphi and towards Lamphun. Water from the city has to go somewhere, and it goes south. In October 2024, as the centre was drying out, parts of Saraphi still had more than a metre of water, people were being evacuated and stretches of the Superhighway were closed. GISTDA's satellite images showed water spreading over farmland, roads and homes in Saraphi, Hang Dong and Lamphun. Flooding downstream tends to come later and last longer than in town, so a house that's fine on day one isn't necessarily fine on day four.

The hills: flash floods. Away from the Ping, the risk is different. Water comes off the mountains fast, with little warning. On the morning of 27 September 2024, a flash flood and mudslides came off Doi Suthep into communities at the foot of the mountain, and Ang Kaeo reservoir at Chiang Mai University overflowed. In Mae Rim, villages along the Mae Sa and Mae Rim rivers flooded four times in less than a month. In Mae Taeng, the Taeng River overflowed in early October and floodwater and landslides cut the roads. If you're looking at a house by a stream in the hills, ask about the water as well as the view.

The places that stayed dry. In October 2024 the Old City, Nimman and the airport weren't hit by the river flood. That doesn't mean the streets never fill in a heavy storm. In 2022 water also came up through drains in town. But it's a very different risk from living on the riverbank.

When floods happen

The Thai Meteorological Department declared the start of the 2026 rainy season on 15 May, and in upper Thailand it usually runs until around mid-October. The dangerous part is the end. The department says tropical storms are most likely in August and September, with the North among the main areas affected. What floods the city is rain upstream: in September 2024 the extra surges came as runoff from heavy rain in Chiang Dao, carried down the Mae Taeng and the upper Ping. The pattern in the river data is clear: of the 37 yearly peaks since 1989, 34 fell between August and October.

If you're visiting from mid-September to mid-October, don't cancel, but book somewhere away from the river, keep plans flexible, and check the river level before you head to the Night Bazaar.

How to check the river yourself

You don't need to wait for the news. The rule of thumb is simple: watch the P.1 reading at Nawarat Bridge against 3.70 m, and watch the trend, not just the number.

RID Upper Northern Hydrology Center

The Royal Irrigation Department's regional site has the live telemetry for P.1 and the stations upstream. Telemetry stations · P.1 station details. It's mostly in Thai, but the numbers are easy to follow.

CMU Water Center (CMFlood)

Chiang Mai University runs a flood site with a forecast for P.1, flood risk maps and a map of the 2024 flood marks. CMFlood flood marks and P.1 forecast.

ThaiWater

The national water data centre, with rain, river levels and dam levels on one map. thaiwater.net.

Weather

The Northern Meteorological Center in Chiang Mai posts forecasts and heavy-rain warnings for the region. cmmet.tmd.go.th.

Official warnings

The Department of Disaster Prevention and Mitigation runs hotline 1784 around the clock, and the LINE account @1784DDPM. disaster.go.th.

If you are renting or buying

This is where a bit of homework pays off. A flood doesn't just mean water in the living room. It can mean a week without a way in or out, a drowned motorbike, or no power. Things I'd ask or check:

Ask directly

Did water come in during 2024? In 2022? How deep, and for how long? Most Chiang Mai landlords and neighbours will tell you straight, and the answer is worth more than any map.

Look for the flood marks

There are about 5,000 flood marks across Chiang Mai and Lamphun showing how deep the October 2024 water got, measured from the road, and the CMU Water Center maps them. If there's one near the place you're looking at, that's your answer.

Check the soi, not just the building

A condo on the eighth floor stays dry, but if the street and car park flood you can still be cut off for days. Ask where people move cars and motorbikes when the river rises.

Ground floors

On a ground floor, look at the height of the floor above the street and of the sockets, the fridge and the fuse box. Ask whether the landlord replaces flooded furniture and appliances.

Read the paperwork

Check what your lease says about flood damage, and whether contents insurance covers flood. Don't assume it does.

If you'd like someone local to help, I've rented and bought through Perfect Homes and would start there. Whoever you use, ask about the flood history of any place on the shortlist.

When the water is coming

Move things early

Get valuables, documents, cars and motorbikes to higher ground as soon as the warnings start, rather than when the water reaches your street.

Stay out of moving water

At least two people died in the October 2024 floods in Chiang Mai. Don't wade, ride or drive through flowing floodwater, and keep children well away from it.

Follow official updates

Use the sources above and local announcements rather than forwarded messages. Water levels fall slowly downstream, so Saraphi and Lamphun can still be rising after town is clear.

Emergency numbers

1784 disaster hotline (DDPM), 1669 ambulance, 191 police, 199 fire, 1155 Tourist Police.

None of this is a reason not to live in Chiang Mai. I still love being near the river. If you live here, the best thing you can do is know your own risk, have a plan, and check on the people around you when the river comes up.