In the affected areas, government authorities are handing out free warm clothing and winter blankets to residents. The north of the country is the worst affected area, with reports that high in the mountains the temperature is just 1C (34F).
One 51-year-old man has already died, apparently because of the sudden heat drop.
Any province in Thailand which ‘suffers’ from more than three consecutive days of sub-15C temperatures can apply for emergency funding.
Explanations for the weather-shift include a cold wind from China brought in by high pressure drift.
Temperatures are unlikely to drop to below 15C in Phuket.