Room In-jae, president of the Ta Faek tambon administration organisation, said the temperature plunged to 9C yesterday morning in the mountainous area close to the Sirikit Dam.
Two people with asthma have died because of the cold weather, Mr Room said.
About 1,385 families in the tambon need blankets and warm clothes, he added.
In the northeastern province of Nakhon Ratchasima, the temperature dropped to 15-17C in the central Phimai district yesterday morning.
The cold snap prompted teachers at Anuban Suriya Uthai Phimai School to organise activities outdoors to keep students warm under the sun.
In Buri Ram, the temperature fell to 13C in Pa Kham district.
Pa Kham district chief Chaiwat Junthirapong cautioned residents about lighting bonfires to keep themselves warm.
Local authorities distributed blankets to more than 1,000 residents, Mr Chaiwat said.