Heavy rain has continued for days. This morning the Meteorological Department issued its 10th warning (226/2569), cautioning of heavy to very heavy rain nationwide until 27 September, with a strong low-pressure cell sitting over the lower Central region, Bangkok and its surrounding provinces. The Thailand flooding situation still needs close watching.
For the Bangkok flooding today, the Governor signed the Bangkok Metropolitan Administration’s public disaster prevention and relief command announcement on disaster-affected areas, expanding the zone from 3 districts and 13 sub-districts – Nong Chok, Suan Luang and Khan Na Yao – to all 50 districts, effective 25 September and announced on 26 September. In the 24 hours from 07:00 on 25 September to 07:00 on 26 September, the BMA Drainage Department’s Thetsaban Songkhro gauge in Chatuchak measured 210.0 millimetres, with four more points above 200 mm: Wang Thonglang 205.5, Saphan Sung 203.5, Phaya Thai 203.0 and Lak Si 201.0. At 07:00 on 26 September there were 44 points of flooding on road surfaces, small vehicles were barred at 7 points, 18 routes were under warning, and 66 points on main roads were being pumped out. Bueng Nong Bon can hold about 5 million cubic metres and was drawn down in advance; roughly 14 million cubic metres of rain fell on eastern Bangkok that night. The Department of Disaster Prevention and Mitigation sent Bangkok a cell broadcast at 09:22 warning that canal levels were critical and rising and telling residents to raise belongings.
The very heavy rain to watch today – the North: Tak and Phetchabun. The Central region: Nakhon Sawan, Uthai Thani, Saraburi, Phra Nakhon Si Ayutthaya, Suphan Buri, Kanchanaburi, Ratchaburi and Nakhon Pathom, plus Bangkok and its surrounding provinces. The East: Nakhon Nayok, Prachin Buri, Chon Buri, Rayong, Chanthaburi and Trat. On 27 September the list narrows to Tak, Kamphaeng Phet, Nakhon Sawan, Uthai Thani, Suphan Buri, Kanchanaburi, Ratchaburi, Bangkok and its surrounding provinces, Nakhon Nayok, Prachin Buri, Chanthaburi and Trat. People in these provinces are watching for Thailand flooding.
Thailand flooding has now hit 12 provinces, 38 districts, 143 sub-districts, 596 villages, 11,796 households and 37,036 people, the Department of Disaster Prevention and Mitigation reported on 25 September – with Suphan Buri and Ayutthaya alone accounting for 10,578 households, or 89.7% of all affected households.
For this round of Bangkok flooding, the Governor declared 3 districts and 13 sub-districts – Nong Chok, Suan Luang and Khan Na Yao – on 25 September, before the declaration expanded to all 50 districts on 26 September. The BMA flood prevention centre announced at 06:42 that small vehicles are barred at 7 points and another 26 road sections are under warning, after 24-hour rainfall at the Pratu Nam Prachachuen measurement point in Min Buri district reached 101.5 millimetres on 25 September.
What makes the Thailand flooding 2026 different from 2011 comes down to Thailand dam levels. The Royal Irrigation Department reported on 25 September 2026 that Bhumibol Dam holds 8,410 million cubic metres (62%) and Sirikit Dam 7,576 million cubic metres (80%) – 15,986 million cubic metres combined, with room for another 6,986 million cubic metres. In 2011, on 26 September, the dams were 94% full, leaving only 1,413 million cubic metres of space.
The Chao Phraya River is still below its banks. Station C.2 in Nakhon Sawan measured 1,795 cubic metres per second on 25 September 2026, 3.53 metres below the bank. In 2011 it was flowing at 4,254 cubic metres per second, 0.43 metres above the bank. The Chao Phraya Dam has raised its discharge from 1,750 to 1,850 cubic metres per second, adding 20 per hour, and is keeping it under 2,000 cubic metres per second.
Bangkok has prepared in advance: drainage in 1,980 canals totalling 2,745 kilometres, 38 monkey-cheek retention areas holding 13.71 million cubic metres, 207 pumping stations, and the Bang O tunnel taking 40 of its 60 cubic metres per second. Seven districts have opened shelters, and the MRTA is offering free parking until 2 October. These are Bangkok’s preparations for Thailand flooding.
Alerts have already reached mobile phones via cell broadcast from the Department of Disaster Prevention and Mitigation with AIS, True and NT, in the areas of Muak Lek (Saraburi), Khao Chamao (Rayong) and Mae Hong Son. The central channels are 1784 and LINE @1784DDPM; BMA help channels: 1555, flood-control centre 0 2248 5115, LINE @TraffyFondue; 1669 for medical emergencies.
On relief, the Finance Ministry’s 2026 criteria pay up to 88,600 baht per house for damaged homes, 4,900 baht per household for fully destroyed homes, and 1,200 baht per person for bedding. A disaster insurance scheme approved in principle by the Cabinet would cover about 30 million households with 75,000 million baht a year.
The Royal Irrigation Department expects the northern water mass to peak around 2 October, while the Meteorological Department expects rain to ease in the Northeast and East during 28-29 September.
Sources:
• Thai Meteorological Department — warning of heavy to very heavy rain across Thailand, Issue 10 (226/2569) — https://www.tmd.go.th/warning-and-events
• Thai Meteorological Department — extended forecast and rain easing 28-29 September 2026 — https://www.tmd.go.th/forecast/sevenday
• Department of Disaster Prevention and Mitigation — disaster situation report and alert channels 1784 / LINE @1784DDPM — https://www.disaster.go.th/home
• Bangkok Metropolitan Administration — declaration of disaster-affected areas and points where small vehicles are barred in Bangkok — https://www.bangkok.go.th
• Mass Rapid Transit Authority of Thailand (MRTA) — free parking for flood-affected people until 2 October 2026 — https://www.thairath.co.th/news/local/bangkok/2962113
• Royal Irrigation Department — daily water situation report, Smart Water Operation Center (SWOC) — https://water.rid.go.th/flood/flood/daily.pdf
• Office of the National Water Resources — water situation data for large dams nationwide — https://nationalthaiwater.onwr.go.th/dam/large
• Ministry of Finance — disaster relief ceilings and 2026 criteria — https://www.prd.go.th/th/content/category/detail/id/39/iid/481275
• Electricity Generating Authority of Thailand and Royal Irrigation Department — comparison of the 2011 and 2026 water situations — https://news.trueid.net/detail/bWA70ZRVdBxM