Phatthanida Sadudee, chief of the Chiang Mai Disaster Prevention and Mitigation Office, said Om Koi and Fang districts has been declared cold-spell disaster zones.
Monday saw the mercury on top of the Doi Inthanon drop to 3 Celsius degrees.
Phattanida said the cold spell was affecting 95 villages in six tambons of Omkoi and atwo villages in Fang.
She said the her office had handed out blankets and sweaters to the people in affected areas and the people living in highland areas has been warned to brace themselves for the cold.