Temperatures in some areas are expected to hit 42°C this dry season, with farmers already being warned to prepare for a prolonged water shortage.
Meteorological Department deputy director-general Thanasith Iamananchai has warned of a long dry spell lasting until mid-May.
"Farmers are advised to manage water as rainfall will be below a 30-year average," he told officials and farmer representatives in Pho Prathap Chang district, Phichit, on Wednesday.
He did not predict dates, but the Meteorological Department website said temperatures could reach the 42°C mark next month in the northern, northeastern and upper central regions.
The Royal Irrigation Office has put up a large sign at the Chao Phraya Dam in Chai Nat asking that farmers help conserve water supplies and maintain the ecosystem by not planting off-season crops.
The message was posted as the water level in the dam reservoir continues to drop. It stands at 15.42 metres above mean sea level, down from 16.51 metres on the same day a year ago.