Thailand faces harsher dry spell as El Niño fuels weather risks, ONWR warns

Thailand is being urged to prepare for more volatile weather through the rest of 2026, with water authorities warning that El Niño could bring a longer dry spell, intense heat, drought pressure and sudden flooding in some areas.

The Office of the National Water Resources (ONWR) said the country is expected to enter a dry spell from late June to mid-July, with this year’s conditions likely to last longer and be more severe than usual.

ONWR Secretary-General Chayan Muangsong said forecasts showed that the dry spell would be influenced mainly by the El Niño phase of the El Niño-Southern Oscillation, or ENSO, which is expected to persist and continue affecting Thailand throughout the year.

The pattern could leave the country facing highly changeable weather, ranging from heatwaves and extreme heat to drought caused by a break in rainfall. At the same time, some areas could still face heavy accumulated rain, flash floods and landslides.

Rainfall across Thailand since the beginning of the year has been around 10% below the normal average, according to ONWR’s assessment. However, authorities are still warning communities to remain alert for flooding, runoff and landslides in areas hit by repeated heavy rain.

As of June 21, the country’s 35 large reservoirs held a combined 44.944 billion cubic metres of water, equal to 56% of total storage capacity. Usable water stood at 20.836 billion cubic metres, or 37% of capacity.

The volume of water stored this year is about 490 million cubic metres lower than in the same period last year.

To reduce the impact on the public, ONWR has instructed all relevant agencies to strictly follow the nine measures for the 2026 rainy season. Agencies have also been told to prepare equipment, machinery and personnel so they can respond quickly if communities need assistance.

ONWR has also coordinated with the Royal Irrigation Department and the Electricity Generating Authority of Thailand to adjust water discharge plans in line with real conditions.

The priority is to keep water levels within standard operating criteria, maintain enough water for all activities and store as much water as possible after the end of the rainy season. Officials are also encouraging the public to use water carefully.

ONWR is monitoring, analysing and assessing weather and water conditions twice a day, in the morning and evening, to support water management planning and improve public warnings.

The agency is also preparing to develop a new rainfall forecasting model, which will be submitted to the subcommittee overseeing water resources management. The model is expected to improve analysis of runoff, flood-risk areas and landslide-prone zones in the future.

Bangkokbiznews