Electricity usage hit a new high at 27,639.3 megawatts on Wednesday night as temperatures soared across the nation.
Soonchai Kumnoonsate, governor of the Electricity Generating Authority of Thailand (Egat), said the new peak was recorded at 8.21pm.
Usage topped the previous record of 27,345.8 megawatts set on June 11.
He said the peak occurred at night as Wednesday was a national holiday, so demand spiked among both households and service providers, such as hotels and restaurants.
Mr Soonchai predicted daily electricity consumption could hit another new peak this year, spurred by daytime demand from industry, services and households.
The Egat governor assured the public that the state enterprise can meet power demands, but he urged people to help lower the load between March 20 and May 20 by keeping air conditioners clean, setting thermostats at 26C, turning off unnecessary lights, and switching to power-saving electric appliances.