Authorities used the same strategy a day earlier at sites where violent clashes had erupted between police and protesters intent on seizing government offices, including the prime minister's compound, known as Government House, and the nearby Metropolitan Police Headquarters, which are in Bangkok's historic district.
The government's move was widely seen as offering demonstrators a face-saving way out of a crisis that has killed five people and wounded at least 277 since the weekend.
The king's birthday holds deep significance in Thailand, and many are looking to the king's traditionally televised speech as an important indicator of how the palace views the protests.
Bhumibol is a constitutional monarch with no formal political role, but he has repeatedly brought calm in times of turbulence and is looked to as a moral guide and unifying figure in Thailand.
Violence on the holiday would be a major sign of disrespect.
As part of the truce, thousands of protesters cleared out of their main gathering point at Democracy Monument.
Cleanup crews scrubbed the sidewalks and streets around the Bangkok landmark, clearing mounds of trash and debris left by the protesters who had camped there for over a week.
